Merge github.com:grpc/grpc into grpc_millis

186 files changed, 7632 insertions, 6306 deletions

diff --git a/src/core/ext/census/README.md b/src/core/ext/census/README.md
index fb615a2194..a9826fe889 100644
--- a/src/core/ext/census/README.md
+++ b/src/core/ext/census/README.md
@@ -1,32 +1,17 @@
 <!---
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
 -->
 
 # Census - a resource measurement and tracing system
diff --git a/src/core/ext/census/aggregation.h b/src/core/ext/census/aggregation.h
index 45f789c772..1ba7953ecc 100644
--- a/src/core/ext/census/aggregation.h
+++ b/src/core/ext/census/aggregation.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/base_resources.c b/src/core/ext/census/base_resources.c
index f9aa4bb994..2114bf04cd 100644
--- a/src/core/ext/census/base_resources.c
+++ b/src/core/ext/census/base_resources.c
@@ -1,32 +1,17 @@
 /*
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/base_resources.h b/src/core/ext/census/base_resources.h
index e5a7696db4..78a4d1fae5 100644
--- a/src/core/ext/census/base_resources.h
+++ b/src/core/ext/census/base_resources.h
@@ -1,32 +1,17 @@
 /*
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_init.c b/src/core/ext/census/census_init.c
index 690b09e789..d7f719ff8c 100644
--- a/src/core/ext/census/census_init.c
+++ b/src/core/ext/census/census_init.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_interface.h b/src/core/ext/census/census_interface.h
index 57e75f56ee..a42b68ad65 100644
--- a/src/core/ext/census/census_interface.h
+++ b/src/core/ext/census/census_interface.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_log.c b/src/core/ext/census/census_log.c
index 9a7331adc2..100047f12b 100644
--- a/src/core/ext/census/census_log.c
+++ b/src/core/ext/census/census_log.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_log.h b/src/core/ext/census/census_log.h
index 1b185a53b9..6b68b6bd37 100644
--- a/src/core/ext/census/census_log.h
+++ b/src/core/ext/census/census_log.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_rpc_stats.c b/src/core/ext/census/census_rpc_stats.c
index 09ee12d54b..0aca1f109e 100644
--- a/src/core/ext/census/census_rpc_stats.c
+++ b/src/core/ext/census/census_rpc_stats.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_rpc_stats.h b/src/core/ext/census/census_rpc_stats.h
index 7e4d8d1640..8004ade37d 100644
--- a/src/core/ext/census/census_rpc_stats.h
+++ b/src/core/ext/census/census_rpc_stats.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_tracing.c b/src/core/ext/census/census_tracing.c
index f893dc9864..199b260dd1 100644
--- a/src/core/ext/census/census_tracing.c
+++ b/src/core/ext/census/census_tracing.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/census_tracing.h b/src/core/ext/census/census_tracing.h
index 42a0d7403e..ccb767fcd0 100644
--- a/src/core/ext/census/census_tracing.h
+++ b/src/core/ext/census/census_tracing.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/context.c b/src/core/ext/census/context.c
index 4195cb1c9b..1019b287d7 100644
--- a/src/core/ext/census/context.c
+++ b/src/core/ext/census/context.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/gen/census.pb.c b/src/core/ext/census/gen/census.pb.c
index 647f0635b7..88efa73661 100644
--- a/src/core/ext/census/gen/census.pb.c
+++ b/src/core/ext/census/gen/census.pb.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 /* Automatically generated nanopb constant definitions */
diff --git a/src/core/ext/census/gen/census.pb.h b/src/core/ext/census/gen/census.pb.h
index c8546eac2e..5f28335664 100644
--- a/src/core/ext/census/gen/census.pb.h
+++ b/src/core/ext/census/gen/census.pb.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 /* Automatically generated nanopb header */
diff --git a/src/core/ext/census/gen/trace_context.pb.c b/src/core/ext/census/gen/trace_context.pb.c
index f4126d4d80..b5c3d52a71 100644
--- a/src/core/ext/census/gen/trace_context.pb.c
+++ b/src/core/ext/census/gen/trace_context.pb.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 /* Automatically generated nanopb constant definitions */
diff --git a/src/core/ext/census/gen/trace_context.pb.h b/src/core/ext/census/gen/trace_context.pb.h
index 6fafc04c81..181925dc9a 100644
--- a/src/core/ext/census/gen/trace_context.pb.h
+++ b/src/core/ext/census/gen/trace_context.pb.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 /* Automatically generated nanopb header */
diff --git a/src/core/ext/census/grpc_context.c b/src/core/ext/census/grpc_context.c
index 98285ab2d5..0bfba63a5e 100644
--- a/src/core/ext/census/grpc_context.c
+++ b/src/core/ext/census/grpc_context.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/grpc_filter.c b/src/core/ext/census/grpc_filter.c
index bcf59a4efe..13fe2e6b1c 100644
--- a/src/core/ext/census/grpc_filter.c
+++ b/src/core/ext/census/grpc_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -156,7 +141,7 @@ static grpc_error *server_init_call_elem(grpc_exec_ctx *exec_ctx,
   memset(d, 0, sizeof(*d));
   d->start_ts = args->start_time;
   /* TODO(hongyu): call census_tracing_start_op here. */
-  grpc_closure_init(&d->finish_recv, server_on_done_recv, elem,
+  GRPC_CLOSURE_INIT(&d->finish_recv, server_on_done_recv, elem,
                     grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
diff --git a/src/core/ext/census/grpc_filter.h b/src/core/ext/census/grpc_filter.h
index a39bd82224..baa7bb931a 100644
--- a/src/core/ext/census/grpc_filter.h
+++ b/src/core/ext/census/grpc_filter.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/grpc_plugin.c b/src/core/ext/census/grpc_plugin.c
index 7d0c9f14ae..c0efe5afb8 100644
--- a/src/core/ext/census/grpc_plugin.c
+++ b/src/core/ext/census/grpc_plugin.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/hash_table.c b/src/core/ext/census/hash_table.c
index ee6fdfc6e8..545b0857c7 100644
--- a/src/core/ext/census/hash_table.c
+++ b/src/core/ext/census/hash_table.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/hash_table.h b/src/core/ext/census/hash_table.h
index 30ea4264a2..75770641c5 100644
--- a/src/core/ext/census/hash_table.h
+++ b/src/core/ext/census/hash_table.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/initialize.c b/src/core/ext/census/initialize.c
index 55cbbe8e95..165a1221d4 100644
--- a/src/core/ext/census/initialize.c
+++ b/src/core/ext/census/initialize.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/intrusive_hash_map.c b/src/core/ext/census/intrusive_hash_map.c
new file mode 100644
index 0000000000..7930486963
--- /dev/null
+++ b/src/core/ext/census/intrusive_hash_map.c
@@ -0,0 +1,305 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/ext/census/intrusive_hash_map.h"
+#include <string.h>
+
+extern bool hm_index_compare(const hm_index *A, const hm_index *B);
+
+/* Simple hashing function that takes lower 32 bits. */
+static __inline uint32_t chunked_vector_hasher(uint64_t key) {
+  return (uint32_t)key;
+}
+
+/* Vector chunks are 1MiB divided by pointer size. */
+static const size_t VECTOR_CHUNK_SIZE = (1 << 20) / sizeof(void *);
+
+/* Helper functions which return buckets from the chunked vector. */
+static __inline void **get_mutable_bucket(const chunked_vector *buckets,
+                                          uint32_t index) {
+  if (index < VECTOR_CHUNK_SIZE) {
+    return &buckets->first_[index];
+  }
+  size_t rest_index = (index - VECTOR_CHUNK_SIZE) / VECTOR_CHUNK_SIZE;
+  return &buckets->rest_[rest_index][index % VECTOR_CHUNK_SIZE];
+}
+
+static __inline void *get_bucket(const chunked_vector *buckets,
+                                 uint32_t index) {
+  if (index < VECTOR_CHUNK_SIZE) {
+    return buckets->first_[index];
+  }
+  size_t rest_index = (index - VECTOR_CHUNK_SIZE) / VECTOR_CHUNK_SIZE;
+  return buckets->rest_[rest_index][index % VECTOR_CHUNK_SIZE];
+}
+
+/* Helper function. */
+static __inline size_t RestSize(const chunked_vector *vec) {
+  return (vec->size_ <= VECTOR_CHUNK_SIZE)
+             ? 0
+             : (vec->size_ - VECTOR_CHUNK_SIZE - 1) / VECTOR_CHUNK_SIZE + 1;
+}
+
+/* Initialize chunked vector to size of 0. */
+static void chunked_vector_init(chunked_vector *vec) {
+  vec->size_ = 0;
+  vec->first_ = NULL;
+  vec->rest_ = NULL;
+}
+
+/* Clear chunked vector and free all memory that has been allocated then
+   initialize chunked vector. */
+static void chunked_vector_clear(chunked_vector *vec) {
+  if (vec->first_ != NULL) {
+    gpr_free(vec->first_);
+  }
+  if (vec->rest_ != NULL) {
+    size_t rest_size = RestSize(vec);
+    for (size_t i = 0; i < rest_size; ++i) {
+      if (vec->rest_[i] != NULL) {
+        gpr_free(vec->rest_[i]);
+      }
+    }
+    gpr_free(vec->rest_);
+  }
+  chunked_vector_init(vec);
+}
+
+/* Clear chunked vector and then resize it to n entries. Allow the first 1MB to
+   be read w/o an extra cache miss. The rest of the elements are stored in an
+   array of arrays to avoid large mallocs. */
+static void chunked_vector_reset(chunked_vector *vec, size_t n) {
+  chunked_vector_clear(vec);
+  vec->size_ = n;
+  if (n <= VECTOR_CHUNK_SIZE) {
+    vec->first_ = (void **)gpr_malloc(sizeof(void *) * n);
+    memset(vec->first_, 0, sizeof(void *) * n);
+  } else {
+    vec->first_ = (void **)gpr_malloc(sizeof(void *) * VECTOR_CHUNK_SIZE);
+    memset(vec->first_, 0, sizeof(void *) * VECTOR_CHUNK_SIZE);
+    size_t rest_size = RestSize(vec);
+    vec->rest_ = (void ***)gpr_malloc(sizeof(void **) * rest_size);
+    memset(vec->rest_, 0, sizeof(void **) * rest_size);
+    int i = 0;
+    n -= VECTOR_CHUNK_SIZE;
+    while (n > 0) {
+      size_t this_size = GPR_MIN(n, VECTOR_CHUNK_SIZE);
+      vec->rest_[i] = (void **)gpr_malloc(sizeof(void *) * this_size);
+      memset(vec->rest_[i], 0, sizeof(void *) * this_size);
+      n -= this_size;
+      ++i;
+    }
+  }
+}
+
+void intrusive_hash_map_init(intrusive_hash_map *hash_map,
+                             uint32_t initial_log2_table_size) {
+  hash_map->log2_num_buckets = initial_log2_table_size;
+  hash_map->num_items = 0;
+  uint32_t num_buckets = (uint32_t)1 << hash_map->log2_num_buckets;
+  hash_map->extend_threshold = num_buckets >> 1;
+  chunked_vector_init(&hash_map->buckets);
+  chunked_vector_reset(&hash_map->buckets, num_buckets);
+  hash_map->hash_mask = num_buckets - 1;
+}
+
+bool intrusive_hash_map_empty(const intrusive_hash_map *hash_map) {
+  return hash_map->num_items == 0;
+}
+
+size_t intrusive_hash_map_size(const intrusive_hash_map *hash_map) {
+  return hash_map->num_items;
+}
+
+void intrusive_hash_map_end(const intrusive_hash_map *hash_map, hm_index *idx) {
+  idx->bucket_index = (uint32_t)hash_map->buckets.size_;
+  GPR_ASSERT(idx->bucket_index <= UINT32_MAX);
+  idx->item = NULL;
+}
+
+void intrusive_hash_map_next(const intrusive_hash_map *hash_map,
+                             hm_index *idx) {
+  idx->item = idx->item->hash_link;
+  while (idx->item == NULL) {
+    idx->bucket_index++;
+    if (idx->bucket_index >= hash_map->buckets.size_) {
+      /* Reached end of table. */
+      idx->item = NULL;
+      return;
+    }
+    idx->item = (hm_item *)get_bucket(&hash_map->buckets, idx->bucket_index);
+  }
+}
+
+void intrusive_hash_map_begin(const intrusive_hash_map *hash_map,
+                              hm_index *idx) {
+  for (uint32_t i = 0; i < hash_map->buckets.size_; ++i) {
+    if (get_bucket(&hash_map->buckets, i) != NULL) {
+      idx->bucket_index = i;
+      idx->item = (hm_item *)get_bucket(&hash_map->buckets, i);
+      return;
+    }
+  }
+  intrusive_hash_map_end(hash_map, idx);
+}
+
+hm_item *intrusive_hash_map_find(const intrusive_hash_map *hash_map,
+                                 uint64_t key) {
+  uint32_t index = chunked_vector_hasher(key) & hash_map->hash_mask;
+
+  hm_item *p = (hm_item *)get_bucket(&hash_map->buckets, index);
+  while (p != NULL) {
+    if (key == p->key) {
+      return p;
+    }
+    p = p->hash_link;
+  }
+  return NULL;
+}
+
+hm_item *intrusive_hash_map_erase(intrusive_hash_map *hash_map, uint64_t key) {
+  uint32_t index = chunked_vector_hasher(key) & hash_map->hash_mask;
+
+  hm_item **slot = (hm_item **)get_mutable_bucket(&hash_map->buckets, index);
+  hm_item *p = *slot;
+  if (p == NULL) {
+    return NULL;
+  }
+
+  if (key == p->key) {
+    *slot = p->hash_link;
+    p->hash_link = NULL;
+    hash_map->num_items--;
+    return p;
+  }
+
+  hm_item *prev = p;
+  p = p->hash_link;
+
+  while (p) {
+    if (key == p->key) {
+      prev->hash_link = p->hash_link;
+      p->hash_link = NULL;
+      hash_map->num_items--;
+      return p;
+    }
+    prev = p;
+    p = p->hash_link;
+  }
+  return NULL;
+}
+
+/* Insert an hm_item* into the underlying chunked vector. hash_mask is
+ * array_size-1. Returns true if it is a new hm_item and false if the hm_item
+ * already existed.
+ */
+static __inline bool intrusive_hash_map_internal_insert(chunked_vector *buckets,
+                                                        uint32_t hash_mask,
+                                                        hm_item *item) {
+  const uint64_t key = item->key;
+  uint32_t index = chunked_vector_hasher(key) & hash_mask;
+  hm_item **slot = (hm_item **)get_mutable_bucket(buckets, index);
+  hm_item *p = *slot;
+  item->hash_link = p;
+
+  /* Check to see if key already exists. */
+  while (p) {
+    if (p->key == key) {
+      return false;
+    }
+    p = p->hash_link;
+  }
+
+  /* Otherwise add new entry. */
+  *slot = item;
+  return true;
+}
+
+/* Extend the allocated number of elements in the hash map by a factor of 2. */
+void intrusive_hash_map_extend(intrusive_hash_map *hash_map) {
+  uint32_t new_log2_num_buckets = 1 + hash_map->log2_num_buckets;
+  uint32_t new_num_buckets = (uint32_t)1 << new_log2_num_buckets;
+  GPR_ASSERT(new_num_buckets <= UINT32_MAX && new_num_buckets > 0);
+  chunked_vector new_buckets;
+  chunked_vector_init(&new_buckets);
+  chunked_vector_reset(&new_buckets, new_num_buckets);
+  uint32_t new_hash_mask = new_num_buckets - 1;
+
+  hm_index cur_idx;
+  hm_index end_idx;
+  intrusive_hash_map_end(hash_map, &end_idx);
+  intrusive_hash_map_begin(hash_map, &cur_idx);
+  while (!hm_index_compare(&cur_idx, &end_idx)) {
+    hm_item *new_item = cur_idx.item;
+    intrusive_hash_map_next(hash_map, &cur_idx);
+    intrusive_hash_map_internal_insert(&new_buckets, new_hash_mask, new_item);
+  }
+
+  /* Set values for new chunked_vector. extend_threshold is set to half of
+   * new_num_buckets. */
+  hash_map->log2_num_buckets = new_log2_num_buckets;
+  chunked_vector_clear(&hash_map->buckets);
+  hash_map->buckets = new_buckets;
+  hash_map->hash_mask = new_hash_mask;
+  hash_map->extend_threshold = new_num_buckets >> 1;
+}
+
+/* Insert a hm_item. The hm_item must remain live until it is removed from the
+   table. This object does not take the ownership of hm_item. The caller must
+   remove this hm_item from the table and delete it before this table is
+   deleted. If hm_item exists already num_items is not changed. */
+bool intrusive_hash_map_insert(intrusive_hash_map *hash_map, hm_item *item) {
+  if (hash_map->num_items >= hash_map->extend_threshold) {
+    intrusive_hash_map_extend(hash_map);
+  }
+  if (intrusive_hash_map_internal_insert(&hash_map->buckets,
+                                         hash_map->hash_mask, item)) {
+    hash_map->num_items++;
+    return true;
+  }
+  return false;
+}
+
+void intrusive_hash_map_clear(intrusive_hash_map *hash_map,
+                              void (*free_object)(void *)) {
+  hm_index cur;
+  hm_index end;
+  intrusive_hash_map_end(hash_map, &end);
+  intrusive_hash_map_begin(hash_map, &cur);
+
+  while (!hm_index_compare(&cur, &end)) {
+    hm_index next = cur;
+    intrusive_hash_map_next(hash_map, &next);
+    if (cur.item != NULL) {
+      hm_item *item = intrusive_hash_map_erase(hash_map, cur.item->key);
+      (*free_object)((void *)item);
+      gpr_free(item);
+    }
+    cur = next;
+  }
+}
+
+void intrusive_hash_map_free(intrusive_hash_map *hash_map,
+                             void (*free_object)(void *)) {
+  intrusive_hash_map_clear(hash_map, (*free_object));
+  hash_map->num_items = 0;
+  hash_map->extend_threshold = 0;
+  hash_map->log2_num_buckets = 0;
+  hash_map->hash_mask = 0;
+  chunked_vector_clear(&hash_map->buckets);
+}
diff --git a/src/core/ext/census/intrusive_hash_map.h b/src/core/ext/census/intrusive_hash_map.h
new file mode 100644
index 0000000000..f50de4fab4
--- /dev/null
+++ b/src/core/ext/census/intrusive_hash_map.h
@@ -0,0 +1,152 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_H
+#define GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_H
+
+#include "src/core/ext/census/intrusive_hash_map_internal.h"
+
+/* intrusive_hash_map is a fast chained hash table. This hash map is faster than
+ * a dense hash map when the application calls insert and erase more often than
+ * find. When the workload is dominated by find() a dense hash map may be
+ * faster.
+ *
+ * intrusive_hash_map uses an intrusive header placed within a user defined
+ * struct. The header field IHM_key MUST be set to a valid value before
+ * insertion into the hash map or undefined behavior may occur. The header field
+ * IHM_hash_link MUST to be set to NULL initially.
+ *
+ * EXAMPLE USAGE:
+ *
+ *  typedef struct string_item {
+ *    INTRUSIVE_HASH_MAP_HEADER;
+ *    // User data.
+ *    char *str_buf;
+ *    uint16_t len;
+ *  } string_item;
+ *
+ *  static string_item *make_string_item(uint64_t key, const char *buf,
+ *                                       uint16_t len) {
+ *    string_item *item = (string_item *)gpr_malloc(sizeof(string_item));
+ *    item->IHM_key = key;
+ *    item->IHM_hash_link = NULL;
+ *    item->len = len;
+ *    item->str_buf = (char *)malloc(len);
+ *    memcpy(item->str_buf, buf, len);
+ *    return item;
+ *  }
+ *
+ *  intrusive_hash_map hash_map;
+ *  intrusive_hash_map_init(&hash_map, 4);
+ *  string_item *new_item1 = make_string_item(10, "test1", 5);
+ *  bool ok = intrusive_hash_map_insert(&hash_map, (hm_item *)new_item1);
+ *
+ *  string_item *item1 =
+ *    (string_item *)intrusive_hash_map_find(&hash_map, 10);
+ */
+
+/* Hash map item. Stores key and a pointer to the actual object. A user defined
+ * version of this can be passed in provided the first 2 entries (key and
+ * hash_link) are the same. These entries must be first in the user defined
+ * struct. Pointer to struct will need to be cast as (hm_item *) when passed to
+ * hash map. This allows it to be intrusive. */
+typedef struct hm_item {
+  uint64_t key;
+  struct hm_item *hash_link;
+  /* Optional user defined data after this. */
+} hm_item;
+
+/* Macro provided for ease of use.  This must be first in the user defined
+ * struct (i.e. uint64_t key and hm_item * must be the first two elements in
+ * that order). */
+#define INTRUSIVE_HASH_MAP_HEADER \
+  uint64_t IHM_key;               \
+  struct hm_item *IHM_hash_link
+
+/* Index struct which acts as a pseudo-iterator within the hash map. */
+typedef struct hm_index {
+  uint32_t bucket_index;  // hash map bucket index.
+  hm_item *item;          // Pointer to hm_item within the hash map.
+} hm_index;
+
+/* Returns true if two hm_indices point to the same object within the hash map
+ * and false otherwise. */
+__inline bool hm_index_compare(const hm_index *A, const hm_index *B) {
+  return (A->item == B->item && A->bucket_index == B->bucket_index);
+}
+
+/*
+ * Helper functions for iterating over the hash map.
+ */
+
+/* On return idx will contain an invalid index which is always equal to
+ * hash_map->buckets.size_ */
+void intrusive_hash_map_end(const intrusive_hash_map *hash_map, hm_index *idx);
+
+/* Iterates index to the next valid entry in the hash map and stores the
+ * index within idx. If end of table is reached, idx will contain the same
+ * values as if intrusive_hash_map_end() was called. */
+void intrusive_hash_map_next(const intrusive_hash_map *hash_map, hm_index *idx);
+
+/* On return, idx will contain the index of the first non-null entry in the hash
+ * map. If the hash map is empty, idx will contain the same values as if
+ * intrusive_hash_map_end() was called. */
+void intrusive_hash_map_begin(const intrusive_hash_map *hash_map,
+                              hm_index *idx);
+
+/* Initialize intrusive hash map data structure. This must be called before
+ * the hash map can be used. The initial size of an intrusive hash map will be
+ * 2^initial_log2_map_size (valid range is [0, 31]). */
+void intrusive_hash_map_init(intrusive_hash_map *hash_map,
+                             uint32_t initial_log2_map_size);
+
+/* Returns true if the hash map is empty and false otherwise. */
+bool intrusive_hash_map_empty(const intrusive_hash_map *hash_map);
+
+/* Returns the number of elements currently in the hash map. */
+size_t intrusive_hash_map_size(const intrusive_hash_map *hash_map);
+
+/* Find a hm_item within the hash map by key. Returns NULL if item was not
+ * found. */
+hm_item *intrusive_hash_map_find(const intrusive_hash_map *hash_map,
+                                 uint64_t key);
+
+/* Erase the hm_item that corresponds with key. If the hm_item is found, return
+ * the pointer to the hm_item. Else returns NULL. */
+hm_item *intrusive_hash_map_erase(intrusive_hash_map *hash_map, uint64_t key);
+
+/* Attempts to insert a new hm_item into the hash map.  If an element with the
+ * same key already exists, it will not insert the new item and return false.
+ * Otherwise, it will insert the new item and return true. */
+bool intrusive_hash_map_insert(intrusive_hash_map *hash_map, hm_item *item);
+
+/* Clears entire contents of the hash map, but leaves internal data structure
+ * untouched. Second argument takes a function pointer to a function that will
+ * free the object designated by the user and pointed to by hash_map->value. */
+void intrusive_hash_map_clear(intrusive_hash_map *hash_map,
+                              void (*free_object)(void *));
+
+/* Erase all contents of hash map and free the memory. Hash map is invalid
+ * after calling this function and cannot be used until it has been
+ * reinitialized (intrusive_hash_map_init()). This function takes a function
+ * pointer to a function that will free the object designated by the user and
+ * pointed to by hash_map->value. */
+void intrusive_hash_map_free(intrusive_hash_map *hash_map,
+                             void (*free_object)(void *));
+
+#endif /* GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_H */
diff --git a/src/core/ext/census/intrusive_hash_map_internal.h b/src/core/ext/census/intrusive_hash_map_internal.h
new file mode 100644
index 0000000000..e9c81fc85c
--- /dev/null
+++ b/src/core/ext/census/intrusive_hash_map_internal.h
@@ -0,0 +1,48 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_INTERNAL_H
+#define GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_INTERNAL_H
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/useful.h>
+#include <stdbool.h>
+
+/* The chunked vector is a data structure that allocates buckets for use in the
+ * hash map. ChunkedVector is logically equivalent to T*[N] (cast void* as
+ * T*). It's internally implemented as an array of 1MB arrays to avoid
+ * allocating large consecutive memory chunks. This is an internal data
+ * structure that should never be accessed directly. */
+typedef struct chunked_vector {
+  size_t size_;
+  void **first_;
+  void ***rest_;
+} chunked_vector;
+
+/* Core intrusive hash map data structure. All internal elements are managed by
+ * functions and should not be altered manually. */
+typedef struct intrusive_hash_map {
+  uint32_t num_items;
+  uint32_t extend_threshold;
+  uint32_t log2_num_buckets;
+  uint32_t hash_mask;
+  chunked_vector buckets;
+} intrusive_hash_map;
+
+#endif /* GRPC_CORE_EXT_CENSUS_INTRUSIVE_HASH_MAP_INTERNAL_H */
diff --git a/src/core/ext/census/mlog.c b/src/core/ext/census/mlog.c
index 698b7096ab..937ceb101b 100644
--- a/src/core/ext/census/mlog.c
+++ b/src/core/ext/census/mlog.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/mlog.h b/src/core/ext/census/mlog.h
index 18805ad994..6f3125944f 100644
--- a/src/core/ext/census/mlog.h
+++ b/src/core/ext/census/mlog.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/operation.c b/src/core/ext/census/operation.c
index 5c58704372..be88ac74e6 100644
--- a/src/core/ext/census/operation.c
+++ b/src/core/ext/census/operation.c
@@ -1,32 +1,17 @@
 /*
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/placeholders.c b/src/core/ext/census/placeholders.c
index 9f99c5bdcf..bed9837ee3 100644
--- a/src/core/ext/census/placeholders.c
+++ b/src/core/ext/census/placeholders.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/resource.c b/src/core/ext/census/resource.c
index 26ea1a8672..1a676f0e1e 100644
--- a/src/core/ext/census/resource.c
+++ b/src/core/ext/census/resource.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/resource.h b/src/core/ext/census/resource.h
index 591bff07da..b8bda2c72e 100644
--- a/src/core/ext/census/resource.h
+++ b/src/core/ext/census/resource.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/rpc_metric_id.h b/src/core/ext/census/rpc_metric_id.h
index 888ec500a7..ea493d7288 100644
--- a/src/core/ext/census/rpc_metric_id.h
+++ b/src/core/ext/census/rpc_metric_id.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_context.c b/src/core/ext/census/trace_context.c
index 47d0de19da..af92ae6d9e 100644
--- a/src/core/ext/census/trace_context.c
+++ b/src/core/ext/census/trace_context.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_context.h b/src/core/ext/census/trace_context.h
index f391a1b7c1..a7233e6a2b 100644
--- a/src/core/ext/census/trace_context.h
+++ b/src/core/ext/census/trace_context.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_label.h b/src/core/ext/census/trace_label.h
index 701f6f5a63..97ce399eb5 100644
--- a/src/core/ext/census/trace_label.h
+++ b/src/core/ext/census/trace_label.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_propagation.h b/src/core/ext/census/trace_propagation.h
index 0c27bfa111..eecfcb7d01 100644
--- a/src/core/ext/census/trace_propagation.h
+++ b/src/core/ext/census/trace_propagation.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_status.h b/src/core/ext/census/trace_status.h
index 0734ec6d3d..dd83d3f729 100644
--- a/src/core/ext/census/trace_status.h
+++ b/src/core/ext/census/trace_status.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/trace_string.h b/src/core/ext/census/trace_string.h
index cd63cfb92f..e4da3f590d 100644
--- a/src/core/ext/census/trace_string.h
+++ b/src/core/ext/census/trace_string.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/tracing.c b/src/core/ext/census/tracing.c
index 8b74628f4f..543a73c5ad 100644
--- a/src/core/ext/census/tracing.c
+++ b/src/core/ext/census/tracing.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/tracing.h b/src/core/ext/census/tracing.h
index 3a7c6f45e4..038c9e2790 100644
--- a/src/core/ext/census/tracing.h
+++ b/src/core/ext/census/tracing.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/window_stats.c b/src/core/ext/census/window_stats.c
index 5f7bd9952e..0058e4bf9c 100644
--- a/src/core/ext/census/window_stats.c
+++ b/src/core/ext/census/window_stats.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/census/window_stats.h b/src/core/ext/census/window_stats.h
index 25658c9ce0..ebe3732008 100644
--- a/src/core/ext/census/window_stats.h
+++ b/src/core/ext/census/window_stats.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/OWNERS b/src/core/ext/filters/client_channel/OWNERS
new file mode 100644
index 0000000000..773bc73179
--- /dev/null
+++ b/src/core/ext/filters/client_channel/OWNERS
@@ -0,0 +1,4 @@
+set noparent
+@markdroth
+@dgquintas
+@ctiller
diff --git a/src/core/ext/filters/client_channel/channel_connectivity.c b/src/core/ext/filters/client_channel/channel_connectivity.c
index 4ccbd5c13d..c3dca14305 100644
--- a/src/core/ext/filters/client_channel/channel_connectivity.c
+++ b/src/core/ext/filters/client_channel/channel_connectivity.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -67,9 +52,8 @@ grpc_connectivity_state grpc_channel_check_connectivity_state(
 
 typedef enum {
   WAITING,
-  CALLING_BACK,
+  READY_TO_CALL_BACK,
   CALLING_BACK_AND_FINISHED,
-  CALLED_BACK
 } callback_phase;
 
 typedef struct {
@@ -77,11 +61,13 @@ typedef struct {
   callback_phase phase;
   grpc_closure on_complete;
   grpc_closure on_timeout;
+  grpc_closure watcher_timer_init;
   grpc_timer alarm;
   grpc_connectivity_state state;
   grpc_completion_queue *cq;
   grpc_cq_completion completion_storage;
   grpc_channel *channel;
+  grpc_error *error;
   void *tag;
 } state_watcher;
 
@@ -105,11 +91,8 @@ static void finished_completion(grpc_exec_ctx *exec_ctx, void *pw,
   gpr_mu_lock(&w->mu);
   switch (w->phase) {
     case WAITING:
-    case CALLED_BACK:
+    case READY_TO_CALL_BACK:
       GPR_UNREACHABLE_CODE(return );
-    case CALLING_BACK:
-      w->phase = CALLED_BACK;
-      break;
     case CALLING_BACK_AND_FINISHED:
       delete = 1;
       break;
@@ -123,10 +106,15 @@ static void finished_completion(grpc_exec_ctx *exec_ctx, void *pw,
 
 static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
                         bool due_to_completion, grpc_error *error) {
-  int delete = 0;
-
   if (due_to_completion) {
     grpc_timer_cancel(exec_ctx, &w->alarm);
+  } else {
+    grpc_channel_element *client_channel_elem = grpc_channel_stack_last_element(
+        grpc_channel_get_channel_stack(w->channel));
+    grpc_client_channel_watch_connectivity_state(
+        exec_ctx, client_channel_elem,
+        grpc_polling_entity_create_from_pollset(grpc_cq_pollset(w->cq)), NULL,
+        &w->on_complete, NULL);
   }
 
   gpr_mu_lock(&w->mu);
@@ -147,25 +135,27 @@ static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
   }
   switch (w->phase) {
     case WAITING:
-      w->phase = CALLING_BACK;
-      grpc_cq_end_op(exec_ctx, w->cq, w->tag, GRPC_ERROR_REF(error),
-                     finished_completion, w, &w->completion_storage);
+      GRPC_ERROR_REF(error);
+      w->error = error;
+      w->phase = READY_TO_CALL_BACK;
       break;
-    case CALLING_BACK:
+    case READY_TO_CALL_BACK:
+      if (error != GRPC_ERROR_NONE) {
+        GPR_ASSERT(!due_to_completion);
+        GRPC_ERROR_UNREF(w->error);
+        GRPC_ERROR_REF(error);
+        w->error = error;
+      }
       w->phase = CALLING_BACK_AND_FINISHED;
+      grpc_cq_end_op(exec_ctx, w->cq, w->tag, w->error, finished_completion, w,
+                     &w->completion_storage);
       break;
     case CALLING_BACK_AND_FINISHED:
       GPR_UNREACHABLE_CODE(return );
-    case CALLED_BACK:
-      delete = 1;
       break;
   }
   gpr_mu_unlock(&w->mu);
 
-  if (delete) {
-    delete_state_watcher(exec_ctx, w);
-  }
-
   GRPC_ERROR_UNREF(error);
 }
 
@@ -179,6 +169,28 @@ static void timeout_complete(grpc_exec_ctx *exec_ctx, void *pw,
   partly_done(exec_ctx, pw, false, GRPC_ERROR_REF(error));
 }
 
+int grpc_channel_num_external_connectivity_watchers(grpc_channel *channel) {
+  grpc_channel_element *client_channel_elem =
+      grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
+  return grpc_client_channel_num_external_connectivity_watchers(
+      client_channel_elem);
+}
+
+typedef struct watcher_timer_init_arg {
+  state_watcher *w;
+  gpr_timespec deadline;
+} watcher_timer_init_arg;
+
+static void watcher_timer_init(grpc_exec_ctx *exec_ctx, void *arg,
+                               grpc_error *error_ignored) {
+  watcher_timer_init_arg *wa = (watcher_timer_init_arg *)arg;
+
+  grpc_timer_init(exec_ctx, &wa->w->alarm,
+                  gpr_convert_clock_type(wa->deadline, GPR_CLOCK_MONOTONIC),
+                  &wa->w->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
+  gpr_free(wa);
+}
+
 void grpc_channel_watch_connectivity_state(
     grpc_channel *channel, grpc_connectivity_state last_observed_state,
     gpr_timespec deadline, grpc_completion_queue *cq, void *tag) {
@@ -199,24 +211,29 @@ void grpc_channel_watch_connectivity_state(
   grpc_cq_begin_op(cq, tag);
 
   gpr_mu_init(&w->mu);
-  grpc_closure_init(&w->on_complete, watch_complete, w,
+  GRPC_CLOSURE_INIT(&w->on_complete, watch_complete, w,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&w->on_timeout, timeout_complete, w,
+  GRPC_CLOSURE_INIT(&w->on_timeout, timeout_complete, w,
                     grpc_schedule_on_exec_ctx);
   w->phase = WAITING;
   w->state = last_observed_state;
   w->cq = cq;
   w->tag = tag;
   w->channel = channel;
+  w->error = NULL;
 
-  grpc_timer_init(&exec_ctx, &w->alarm,
-                  grpc_timespec_to_millis(&exec_ctx, deadline), &w->on_timeout);
+  watcher_timer_init_arg *wa = gpr_malloc(sizeof(watcher_timer_init_arg));
+  wa->w = w;
+  wa->deadline = deadline;
+  GRPC_CLOSURE_INIT(&w->watcher_timer_init, watcher_timer_init, wa,
+                    grpc_schedule_on_exec_ctx);
 
   if (client_channel_elem->filter == &grpc_client_channel_filter) {
     GRPC_CHANNEL_INTERNAL_REF(channel, "watch_channel_connectivity");
-    grpc_client_channel_watch_connectivity_state(&exec_ctx, client_channel_elem,
-                                                 grpc_cq_pollset(cq), &w->state,
-                                                 &w->on_complete);
+    grpc_client_channel_watch_connectivity_state(
+        &exec_ctx, client_channel_elem,
+        grpc_polling_entity_create_from_pollset(grpc_cq_pollset(cq)), &w->state,
+        &w->on_complete, &w->watcher_timer_init);
   } else {
     abort();
   }
diff --git a/src/core/ext/filters/client_channel/client_channel.c b/src/core/ext/filters/client_channel/client_channel.c
index 24843d52e9..58e31d7b45 100644
--- a/src/core/ext/filters/client_channel/client_channel.c
+++ b/src/core/ext/filters/client_channel/client_channel.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -67,6 +52,9 @@
 
 /* Client channel implementation */
 
+grpc_tracer_flag grpc_client_channel_trace =
+    GRPC_TRACER_INITIALIZER(false, "client_channel");
+
 /*************************************************************************
  * METHOD-CONFIG TABLE
  */
@@ -167,6 +155,8 @@ static void *method_parameters_create_from_json(const grpc_json *json) {
   return value;
 }
 
+struct external_connectivity_watcher;
+
 /*************************************************************************
  * CHANNEL-WIDE FUNCTIONS
  */
@@ -191,8 +181,8 @@ typedef struct client_channel_channel_data {
   grpc_slice_hash_table *method_params_table;
   /** incoming resolver result - set by resolver.next() */
   grpc_channel_args *resolver_result;
-  /** a list of closures that are all waiting for config to come in */
-  grpc_closure_list waiting_for_config_closures;
+  /** a list of closures that are all waiting for resolver result to come in */
+  grpc_closure_list waiting_for_resolver_result_closures;
   /** resolver callback */
   grpc_closure on_resolver_result_changed;
   /** connectivity state being tracked */
@@ -204,6 +194,11 @@ typedef struct client_channel_channel_data {
   /** interested parties (owned) */
   grpc_pollset_set *interested_parties;
 
+  /* external_connectivity_watcher_list head is guarded by its own mutex, since
+   * counts need to be grabbed immediately without polling on a cq */
+  gpr_mu external_connectivity_watcher_list_mu;
+  struct external_connectivity_watcher *external_connectivity_watcher_list_head;
+
   /* the following properties are guarded by a mutex since API's require them
      to be instantaneously available */
   gpr_mu info_mu;
@@ -249,6 +244,10 @@ static void set_channel_connectivity_state_locked(grpc_exec_ctx *exec_ctx,
                                          GRPC_ERROR_REF(error));
     }
   }
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p: setting connectivity state to %s", chand,
+            grpc_connectivity_state_name(state));
+  }
   grpc_connectivity_state_set(exec_ctx, &chand->state_tracker, state, error,
                               reason);
 }
@@ -259,6 +258,10 @@ static void on_lb_policy_state_changed_locked(grpc_exec_ctx *exec_ctx,
   grpc_connectivity_state publish_state = w->state;
   /* check if the notification is for the latest policy */
   if (w->lb_policy == w->chand->lb_policy) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p: lb_policy=%p state changed to %s", w->chand,
+              w->lb_policy, grpc_connectivity_state_name(w->state));
+    }
     if (publish_state == GRPC_CHANNEL_SHUTDOWN && w->chand->resolver != NULL) {
       publish_state = GRPC_CHANNEL_TRANSIENT_FAILURE;
       grpc_resolver_channel_saw_error_locked(exec_ctx, w->chand->resolver);
@@ -271,7 +274,6 @@ static void on_lb_policy_state_changed_locked(grpc_exec_ctx *exec_ctx,
       watch_lb_policy_locked(exec_ctx, w->chand, w->lb_policy, w->state);
     }
   }
-
   GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack, "watch_lb_policy");
   gpr_free(w);
 }
@@ -281,16 +283,27 @@ static void watch_lb_policy_locked(grpc_exec_ctx *exec_ctx, channel_data *chand,
                                    grpc_connectivity_state current_state) {
   lb_policy_connectivity_watcher *w = gpr_malloc(sizeof(*w));
   GRPC_CHANNEL_STACK_REF(chand->owning_stack, "watch_lb_policy");
-
   w->chand = chand;
-  grpc_closure_init(&w->on_changed, on_lb_policy_state_changed_locked, w,
-                    grpc_combiner_scheduler(chand->combiner, false));
+  GRPC_CLOSURE_INIT(&w->on_changed, on_lb_policy_state_changed_locked, w,
+                    grpc_combiner_scheduler(chand->combiner));
   w->state = current_state;
   w->lb_policy = lb_policy;
   grpc_lb_policy_notify_on_state_change_locked(exec_ctx, lb_policy, &w->state,
                                                &w->on_changed);
 }
 
+static void start_resolving_locked(grpc_exec_ctx *exec_ctx,
+                                   channel_data *chand) {
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p: starting name resolution", chand);
+  }
+  GPR_ASSERT(!chand->started_resolving);
+  chand->started_resolving = true;
+  GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
+  grpc_resolver_next_locked(exec_ctx, chand->resolver, &chand->resolver_result,
+                            &chand->on_resolver_result_changed);
+}
+
 typedef struct {
   char *server_name;
   grpc_server_retry_throttle_data *retry_throttle_data;
@@ -350,48 +363,21 @@ static void parse_retry_throttle_params(const grpc_json *field, void *arg) {
   }
 }
 
-// Wrap a closure associated with \a lb_policy. The associated callback (\a
-// wrapped_on_pick_closure_cb) is responsible for unref'ing \a lb_policy after
-// scheduling \a wrapped_closure.
-typedef struct wrapped_on_pick_closure_arg {
-  /* the closure instance using this struct as argument */
-  grpc_closure wrapper_closure;
-
-  /* the original closure. Usually a on_complete/notify cb for pick() and ping()
-   * calls against the internal RR instance, respectively. */
-  grpc_closure *wrapped_closure;
-
-  /* The policy instance related to the closure */
-  grpc_lb_policy *lb_policy;
-} wrapped_on_pick_closure_arg;
-
-// Invoke \a arg->wrapped_closure, unref \a arg->lb_policy and free \a arg.
-static void wrapped_on_pick_closure_cb(grpc_exec_ctx *exec_ctx, void *arg,
-                                       grpc_error *error) {
-  wrapped_on_pick_closure_arg *wc_arg = arg;
-  GPR_ASSERT(wc_arg != NULL);
-  GPR_ASSERT(wc_arg->wrapped_closure != NULL);
-  GPR_ASSERT(wc_arg->lb_policy != NULL);
-  grpc_closure_run(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error));
-  GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->lb_policy, "pick_subchannel_wrapping");
-  gpr_free(wc_arg);
-}
-
 static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
                                               void *arg, grpc_error *error) {
   channel_data *chand = arg;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p: got resolver result: error=%s", chand,
+            grpc_error_string(error));
+  }
+  // Extract the following fields from the resolver result, if non-NULL.
+  bool lb_policy_updated = false;
   char *lb_policy_name = NULL;
-  grpc_lb_policy *lb_policy = NULL;
-  grpc_lb_policy *old_lb_policy;
-  grpc_slice_hash_table *method_params_table = NULL;
-  grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
-  bool exit_idle = false;
-  grpc_error *state_error =
-      GRPC_ERROR_CREATE_FROM_STATIC_STRING("No load balancing policy");
+  bool lb_policy_name_changed = false;
+  grpc_lb_policy *new_lb_policy = NULL;
   char *service_config_json = NULL;
-  service_config_parsing_state parsing_state;
-  memset(&parsing_state, 0, sizeof(parsing_state));
-
+  grpc_server_retry_throttle_data *retry_throttle_data = NULL;
+  grpc_slice_hash_table *method_params_table = NULL;
   if (chand->resolver_result != NULL) {
     // Find LB policy name.
     const grpc_arg *channel_arg =
@@ -426,18 +412,29 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
     // Use pick_first if nothing was specified and we didn't select grpclb
     // above.
     if (lb_policy_name == NULL) lb_policy_name = "pick_first";
-    // Instantiate LB policy.
     grpc_lb_policy_args lb_policy_args;
     lb_policy_args.args = chand->resolver_result;
     lb_policy_args.client_channel_factory = chand->client_channel_factory;
     lb_policy_args.combiner = chand->combiner;
-    lb_policy =
-        grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args);
-    if (lb_policy != NULL) {
-      GRPC_LB_POLICY_REF(lb_policy, "config_change");
-      GRPC_ERROR_UNREF(state_error);
-      state = grpc_lb_policy_check_connectivity_locked(exec_ctx, lb_policy,
-                                                       &state_error);
+    // Check to see if we're already using the right LB policy.
+    // Note: It's safe to use chand->info_lb_policy_name here without
+    // taking a lock on chand->info_mu, because this function is the
+    // only thing that modifies its value, and it can only be invoked
+    // once at any given time.
+    lb_policy_name_changed =
+        chand->info_lb_policy_name == NULL ||
+        strcmp(chand->info_lb_policy_name, lb_policy_name) != 0;
+    if (chand->lb_policy != NULL && !lb_policy_name_changed) {
+      // Continue using the same LB policy.  Update with new addresses.
+      lb_policy_updated = true;
+      grpc_lb_policy_update_locked(exec_ctx, chand->lb_policy, &lb_policy_args);
+    } else {
+      // Instantiate new LB policy.
+      new_lb_policy =
+          grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args);
+      if (new_lb_policy == NULL) {
+        gpr_log(GPR_ERROR, "could not create LB policy \"%s\"", lb_policy_name);
+      }
     }
     // Find service config.
     channel_arg =
@@ -455,12 +452,14 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
         grpc_uri *uri =
             grpc_uri_parse(exec_ctx, channel_arg->value.string, true);
         GPR_ASSERT(uri->path[0] != '\0');
+        service_config_parsing_state parsing_state;
+        memset(&parsing_state, 0, sizeof(parsing_state));
         parsing_state.server_name =
             uri->path[0] == '/' ? uri->path + 1 : uri->path;
         grpc_service_config_parse_global_params(
             service_config, parse_retry_throttle_params, &parsing_state);
-        parsing_state.server_name = NULL;
         grpc_uri_destroy(uri);
+        retry_throttle_data = parsing_state.retry_throttle_data;
         method_params_table = grpc_service_config_create_method_config_table(
             exec_ctx, service_config, method_parameters_create_from_json,
             method_parameters_free);
@@ -474,88 +473,115 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
     grpc_channel_args_destroy(exec_ctx, chand->resolver_result);
     chand->resolver_result = NULL;
   }
-
-  if (lb_policy != NULL) {
-    grpc_pollset_set_add_pollset_set(exec_ctx, lb_policy->interested_parties,
-                                     chand->interested_parties);
-  }
-
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG,
+            "chand=%p: resolver result: lb_policy_name=\"%s\"%s, "
+            "service_config=\"%s\"",
+            chand, lb_policy_name, lb_policy_name_changed ? " (changed)" : "",
+            service_config_json);
+  }
+  // Now swap out fields in chand.  Note that the new values may still
+  // be NULL if (e.g.) the resolver failed to return results or the
+  // results did not contain the necessary data.
+  //
+  // First, swap out the data used by cc_get_channel_info().
   gpr_mu_lock(&chand->info_mu);
   if (lb_policy_name != NULL) {
     gpr_free(chand->info_lb_policy_name);
     chand->info_lb_policy_name = lb_policy_name;
   }
-  old_lb_policy = chand->lb_policy;
-  chand->lb_policy = lb_policy;
   if (service_config_json != NULL) {
     gpr_free(chand->info_service_config_json);
     chand->info_service_config_json = service_config_json;
   }
   gpr_mu_unlock(&chand->info_mu);
-
+  // Swap out the retry throttle data.
   if (chand->retry_throttle_data != NULL) {
     grpc_server_retry_throttle_data_unref(chand->retry_throttle_data);
   }
-  chand->retry_throttle_data = parsing_state.retry_throttle_data;
+  chand->retry_throttle_data = retry_throttle_data;
+  // Swap out the method params table.
   if (chand->method_params_table != NULL) {
     grpc_slice_hash_table_unref(exec_ctx, chand->method_params_table);
   }
   chand->method_params_table = method_params_table;
-  if (lb_policy != NULL) {
-    grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
-  } else if (chand->resolver == NULL /* disconnected */) {
-    grpc_closure_list_fail_all(&chand->waiting_for_config_closures,
-                               GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-                                   "Channel disconnected", &error, 1));
-    grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
-  }
-  if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) {
-    GRPC_LB_POLICY_REF(lb_policy, "exit_idle");
-    exit_idle = true;
-    chand->exit_idle_when_lb_policy_arrives = false;
+  // If we have a new LB policy or are shutting down (in which case
+  // new_lb_policy will be NULL), swap out the LB policy, unreffing the
+  // old one and removing its fds from chand->interested_parties.
+  // Note that we do NOT do this if either (a) we updated the existing
+  // LB policy above or (b) we failed to create the new LB policy (in
+  // which case we want to continue using the most recent one we had).
+  if (new_lb_policy != NULL || error != GRPC_ERROR_NONE ||
+      chand->resolver == NULL) {
+    if (chand->lb_policy != NULL) {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG, "chand=%p: unreffing lb_policy=%p", chand,
+                chand->lb_policy);
+      }
+      grpc_pollset_set_del_pollset_set(exec_ctx,
+                                       chand->lb_policy->interested_parties,
+                                       chand->interested_parties);
+      GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel");
+    }
+    chand->lb_policy = new_lb_policy;
   }
-
-  if (error == GRPC_ERROR_NONE && chand->resolver) {
-    set_channel_connectivity_state_locked(
-        exec_ctx, chand, state, GRPC_ERROR_REF(state_error), "new_lb+resolver");
-    if (lb_policy != NULL) {
-      watch_lb_policy_locked(exec_ctx, chand, lb_policy, state);
+  // Now that we've swapped out the relevant fields of chand, check for
+  // error or shutdown.
+  if (error != GRPC_ERROR_NONE || chand->resolver == NULL) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p: shutting down", chand);
     }
-    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
-    grpc_resolver_next_locked(exec_ctx, chand->resolver,
-                              &chand->resolver_result,
-                              &chand->on_resolver_result_changed);
-  } else {
     if (chand->resolver != NULL) {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG, "chand=%p: shutting down resolver", chand);
+      }
       grpc_resolver_shutdown_locked(exec_ctx, chand->resolver);
       GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
       chand->resolver = NULL;
     }
-    grpc_error *refs[] = {error, state_error};
     set_channel_connectivity_state_locked(
         exec_ctx, chand, GRPC_CHANNEL_SHUTDOWN,
         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-            "Got config after disconnection", refs, GPR_ARRAY_SIZE(refs)),
+            "Got resolver result after disconnection", &error, 1),
         "resolver_gone");
+    GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
+    grpc_closure_list_fail_all(&chand->waiting_for_resolver_result_closures,
+                               GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                                   "Channel disconnected", &error, 1));
+    GRPC_CLOSURE_LIST_SCHED(exec_ctx,
+                            &chand->waiting_for_resolver_result_closures);
+  } else {  // Not shutting down.
+    grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
+    grpc_error *state_error =
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("No load balancing policy");
+    if (new_lb_policy != NULL) {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG, "chand=%p: initializing new LB policy", chand);
+      }
+      GRPC_ERROR_UNREF(state_error);
+      state = grpc_lb_policy_check_connectivity_locked(exec_ctx, new_lb_policy,
+                                                       &state_error);
+      grpc_pollset_set_add_pollset_set(exec_ctx,
+                                       new_lb_policy->interested_parties,
+                                       chand->interested_parties);
+      GRPC_CLOSURE_LIST_SCHED(exec_ctx,
+                              &chand->waiting_for_resolver_result_closures);
+      if (chand->exit_idle_when_lb_policy_arrives) {
+        grpc_lb_policy_exit_idle_locked(exec_ctx, new_lb_policy);
+        chand->exit_idle_when_lb_policy_arrives = false;
+      }
+      watch_lb_policy_locked(exec_ctx, chand, new_lb_policy, state);
+    }
+    if (!lb_policy_updated) {
+      set_channel_connectivity_state_locked(exec_ctx, chand, state,
+                                            GRPC_ERROR_REF(state_error),
+                                            "new_lb+resolver");
+    }
+    grpc_resolver_next_locked(exec_ctx, chand->resolver,
+                              &chand->resolver_result,
+                              &chand->on_resolver_result_changed);
+    GRPC_ERROR_UNREF(state_error);
   }
-
-  if (exit_idle) {
-    grpc_lb_policy_exit_idle_locked(exec_ctx, lb_policy);
-    GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "exit_idle");
-  }
-
-  if (old_lb_policy != NULL) {
-    grpc_pollset_set_del_pollset_set(
-        exec_ctx, old_lb_policy->interested_parties, chand->interested_parties);
-    GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel");
-  }
-
-  if (lb_policy != NULL) {
-    GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change");
-  }
-
-  GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver");
-  GRPC_ERROR_UNREF(state_error);
 }
 
 static void start_transport_op_locked(grpc_exec_ctx *exec_ctx, void *arg,
@@ -574,7 +600,7 @@ static void start_transport_op_locked(grpc_exec_ctx *exec_ctx, void *arg,
 
   if (op->send_ping != NULL) {
     if (chand->lb_policy == NULL) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx, op->send_ping,
           GRPC_ERROR_CREATE_FROM_STATIC_STRING("Ping with no load balancing"));
     } else {
@@ -593,9 +619,10 @@ static void start_transport_op_locked(grpc_exec_ctx *exec_ctx, void *arg,
       GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
       chand->resolver = NULL;
       if (!chand->started_resolving) {
-        grpc_closure_list_fail_all(&chand->waiting_for_config_closures,
+        grpc_closure_list_fail_all(&chand->waiting_for_resolver_result_closures,
                                    GRPC_ERROR_REF(op->disconnect_with_error));
-        grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
+        GRPC_CLOSURE_LIST_SCHED(exec_ctx,
+                                &chand->waiting_for_resolver_result_closures);
       }
       if (chand->lb_policy != NULL) {
         grpc_pollset_set_del_pollset_set(exec_ctx,
@@ -609,7 +636,7 @@ static void start_transport_op_locked(grpc_exec_ctx *exec_ctx, void *arg,
   }
   GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "start_transport_op");
 
-  grpc_closure_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
 }
 
 static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
@@ -625,10 +652,10 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
 
   op->handler_private.extra_arg = elem;
   GRPC_CHANNEL_STACK_REF(chand->owning_stack, "start_transport_op");
-  grpc_closure_sched(
+  GRPC_CLOSURE_SCHED(
       exec_ctx,
-      grpc_closure_init(&op->handler_private.closure, start_transport_op_locked,
-                        op, grpc_combiner_scheduler(chand->combiner, false)),
+      GRPC_CLOSURE_INIT(&op->handler_private.closure, start_transport_op_locked,
+                        op, grpc_combiner_scheduler(chand->combiner)),
       GRPC_ERROR_NONE);
 }
 
@@ -659,12 +686,18 @@ static grpc_error *cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(args->is_last);
   GPR_ASSERT(elem->filter == &grpc_client_channel_filter);
   // Initialize data members.
-  chand->combiner = grpc_combiner_create(NULL);
+  chand->combiner = grpc_combiner_create();
   gpr_mu_init(&chand->info_mu);
+  gpr_mu_init(&chand->external_connectivity_watcher_list_mu);
+
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  chand->external_connectivity_watcher_list_head = NULL;
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+
   chand->owning_stack = args->channel_stack;
-  grpc_closure_init(&chand->on_resolver_result_changed,
+  GRPC_CLOSURE_INIT(&chand->on_resolver_result_changed,
                     on_resolver_result_changed_locked, chand,
-                    grpc_combiner_scheduler(chand->combiner, false));
+                    grpc_combiner_scheduler(chand->combiner));
   chand->interested_parties = grpc_pollset_set_create();
   grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
                                "client_channel");
@@ -722,10 +755,9 @@ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                     grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
   if (chand->resolver != NULL) {
-    grpc_closure_sched(
-        exec_ctx,
-        grpc_closure_create(shutdown_resolver_locked, chand->resolver,
-                            grpc_combiner_scheduler(chand->combiner, false)),
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, GRPC_CLOSURE_CREATE(shutdown_resolver_locked, chand->resolver,
+                                      grpc_combiner_scheduler(chand->combiner)),
         GRPC_ERROR_NONE);
   }
   if (chand->client_channel_factory != NULL) {
@@ -749,16 +781,22 @@ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   grpc_pollset_set_destroy(exec_ctx, chand->interested_parties);
   GRPC_COMBINER_UNREF(exec_ctx, chand->combiner, "client_channel");
   gpr_mu_destroy(&chand->info_mu);
+  gpr_mu_destroy(&chand->external_connectivity_watcher_list_mu);
 }
 
 /*************************************************************************
  * PER-CALL FUNCTIONS
  */
 
-#define GET_CALL(call_data) \
-  ((grpc_subchannel_call *)(gpr_atm_acq_load(&(call_data)->subchannel_call)))
-
-#define CANCELLED_CALL ((grpc_subchannel_call *)1)
+// Max number of batches that can be pending on a call at any given
+// time.  This includes:
+//   recv_initial_metadata
+//   send_initial_metadata
+//   recv_message
+//   send_message
+//   recv_trailing_metadata
+//   send_trailing_metadata
+#define MAX_WAITING_BATCHES 6
 
 /** Call data.  Holds a pointer to grpc_subchannel_call and the
     associated machinery to create such a pointer.
@@ -780,23 +818,22 @@ typedef struct client_channel_call_data {
   grpc_server_retry_throttle_data *retry_throttle_data;
   method_parameters *method_params;
 
-  grpc_error *cancel_error;
-
-  /** either 0 for no call, 1 for cancelled, or a pointer to a
-      grpc_subchannel_call */
-  gpr_atm subchannel_call;
+  /** either 0 for no call, a pointer to a grpc_subchannel_call (if the lowest
+      bit is 0), or a pointer to an error (if the lowest bit is 1) */
+  gpr_atm subchannel_call_or_error;
   gpr_arena *arena;
 
-  bool pick_pending;
+  grpc_lb_policy *lb_policy;  // Holds ref while LB pick is pending.
+  grpc_closure lb_pick_closure;
+
   grpc_connected_subchannel *connected_subchannel;
   grpc_call_context_element subchannel_call_context[GRPC_CONTEXT_COUNT];
   grpc_polling_entity *pollent;
 
-  grpc_transport_stream_op_batch **waiting_ops;
-  size_t waiting_ops_count;
-  size_t waiting_ops_capacity;
+  grpc_transport_stream_op_batch *waiting_for_pick_batches[MAX_WAITING_BATCHES];
+  size_t waiting_for_pick_batches_count;
 
-  grpc_closure next_step;
+  grpc_transport_stream_op_batch_payload *initial_metadata_payload;
 
   grpc_call_stack *owning_call;
 
@@ -806,65 +843,103 @@ typedef struct client_channel_call_data {
   grpc_closure *original_on_complete;
 } call_data;
 
+typedef struct {
+  grpc_subchannel_call *subchannel_call;
+  grpc_error *error;
+} call_or_error;
+
+static call_or_error get_call_or_error(call_data *p) {
+  gpr_atm c = gpr_atm_acq_load(&p->subchannel_call_or_error);
+  if (c == 0)
+    return (call_or_error){NULL, NULL};
+  else if (c & 1)
+    return (call_or_error){NULL, (grpc_error *)((c) & ~(gpr_atm)1)};
+  else
+    return (call_or_error){(grpc_subchannel_call *)c, NULL};
+}
+
+static bool set_call_or_error(call_data *p, call_or_error coe) {
+  // this should always be under a lock
+  call_or_error existing = get_call_or_error(p);
+  if (existing.error != GRPC_ERROR_NONE) {
+    GRPC_ERROR_UNREF(coe.error);
+    return false;
+  }
+  GPR_ASSERT(existing.subchannel_call == NULL);
+  if (coe.error != GRPC_ERROR_NONE) {
+    GPR_ASSERT(coe.subchannel_call == NULL);
+    gpr_atm_rel_store(&p->subchannel_call_or_error, 1 | (gpr_atm)coe.error);
+  } else {
+    GPR_ASSERT(coe.subchannel_call != NULL);
+    gpr_atm_rel_store(&p->subchannel_call_or_error,
+                      (gpr_atm)coe.subchannel_call);
+  }
+  return true;
+}
+
 grpc_subchannel_call *grpc_client_channel_get_subchannel_call(
     grpc_call_element *call_elem) {
-  grpc_subchannel_call *scc = GET_CALL((call_data *)call_elem->call_data);
-  return scc == CANCELLED_CALL ? NULL : scc;
+  return get_call_or_error(call_elem->call_data).subchannel_call;
 }
 
-static void add_waiting_locked(call_data *calld,
-                               grpc_transport_stream_op_batch *op) {
-  GPR_TIMER_BEGIN("add_waiting_locked", 0);
-  if (calld->waiting_ops_count == calld->waiting_ops_capacity) {
-    calld->waiting_ops_capacity = GPR_MAX(3, 2 * calld->waiting_ops_capacity);
-    calld->waiting_ops =
-        gpr_realloc(calld->waiting_ops,
-                    calld->waiting_ops_capacity * sizeof(*calld->waiting_ops));
-  }
-  calld->waiting_ops[calld->waiting_ops_count++] = op;
-  GPR_TIMER_END("add_waiting_locked", 0);
+static void waiting_for_pick_batches_add_locked(
+    call_data *calld, grpc_transport_stream_op_batch *batch) {
+  GPR_ASSERT(calld->waiting_for_pick_batches_count < MAX_WAITING_BATCHES);
+  calld->waiting_for_pick_batches[calld->waiting_for_pick_batches_count++] =
+      batch;
 }
 
-static void fail_locked(grpc_exec_ctx *exec_ctx, call_data *calld,
-                        grpc_error *error) {
-  size_t i;
-  for (i = 0; i < calld->waiting_ops_count; i++) {
+static void waiting_for_pick_batches_fail_locked(grpc_exec_ctx *exec_ctx,
+                                                 grpc_call_element *elem,
+                                                 grpc_error *error) {
+  call_data *calld = elem->call_data;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG,
+            "chand=%p calld=%p: failing %" PRIdPTR " pending batches: %s",
+            elem->channel_data, calld, calld->waiting_for_pick_batches_count,
+            grpc_error_string(error));
+  }
+  for (size_t i = 0; i < calld->waiting_for_pick_batches_count; ++i) {
     grpc_transport_stream_op_batch_finish_with_failure(
-        exec_ctx, calld->waiting_ops[i], GRPC_ERROR_REF(error));
+        exec_ctx, calld->waiting_for_pick_batches[i], GRPC_ERROR_REF(error));
   }
-  calld->waiting_ops_count = 0;
+  calld->waiting_for_pick_batches_count = 0;
   GRPC_ERROR_UNREF(error);
 }
 
-static void retry_waiting_locked(grpc_exec_ctx *exec_ctx, call_data *calld) {
-  if (calld->waiting_ops_count == 0) {
+static void waiting_for_pick_batches_resume_locked(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem) {
+  call_data *calld = elem->call_data;
+  if (calld->waiting_for_pick_batches_count == 0) return;
+  call_or_error coe = get_call_or_error(calld);
+  if (coe.error != GRPC_ERROR_NONE) {
+    waiting_for_pick_batches_fail_locked(exec_ctx, elem,
+                                         GRPC_ERROR_REF(coe.error));
     return;
   }
-
-  grpc_subchannel_call *call = GET_CALL(calld);
-  grpc_transport_stream_op_batch **ops = calld->waiting_ops;
-  size_t nops = calld->waiting_ops_count;
-  if (call == CANCELLED_CALL) {
-    fail_locked(exec_ctx, calld, GRPC_ERROR_CANCELLED);
-    return;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: sending %" PRIdPTR
+                       " pending batches to subchannel_call=%p",
+            elem->channel_data, calld, calld->waiting_for_pick_batches_count,
+            coe.subchannel_call);
   }
-  calld->waiting_ops = NULL;
-  calld->waiting_ops_count = 0;
-  calld->waiting_ops_capacity = 0;
-  for (size_t i = 0; i < nops; i++) {
-    grpc_subchannel_call_process_op(exec_ctx, call, ops[i]);
+  for (size_t i = 0; i < calld->waiting_for_pick_batches_count; ++i) {
+    grpc_subchannel_call_process_op(exec_ctx, coe.subchannel_call,
+                                    calld->waiting_for_pick_batches[i]);
   }
-  gpr_free(ops);
+  calld->waiting_for_pick_batches_count = 0;
 }
 
-// Sets calld->method_params and calld->retry_throttle_data.
-// If the method params specify a timeout, populates
-// *per_method_deadline and returns true.
-static bool set_call_method_params_from_service_config_locked(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-    gpr_timespec *per_method_deadline) {
+// Applies service config to the call.  Must be invoked once we know
+// that the resolver has returned results to the channel.
+static void apply_service_config_to_call_locked(grpc_exec_ctx *exec_ctx,
+                                                grpc_call_element *elem) {
   channel_data *chand = elem->channel_data;
   call_data *calld = elem->call_data;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: applying service config to call",
+            chand, calld);
+  }
   if (chand->retry_throttle_data != NULL) {
     calld->retry_throttle_data =
         grpc_server_retry_throttle_data_ref(chand->retry_throttle_data);
@@ -874,175 +949,283 @@ static bool set_call_method_params_from_service_config_locked(
         exec_ctx, chand->method_params_table, calld->path);
     if (calld->method_params != NULL) {
       method_parameters_ref(calld->method_params);
-      if (gpr_time_cmp(calld->method_params->timeout,
+      // If the deadline from the service config is shorter than the one
+      // from the client API, reset the deadline timer.
+      if (chand->deadline_checking_enabled &&
+          gpr_time_cmp(calld->method_params->timeout,
                        gpr_time_0(GPR_TIMESPAN)) != 0) {
-        *per_method_deadline =
+        const gpr_timespec per_method_deadline =
             gpr_time_add(calld->call_start_time, calld->method_params->timeout);
-        return true;
+        if (gpr_time_cmp(per_method_deadline, calld->deadline) < 0) {
+          calld->deadline = per_method_deadline;
+          grpc_deadline_state_reset(exec_ctx, elem, calld->deadline);
+        }
       }
     }
   }
-  return false;
 }
 
-static void apply_final_configuration_locked(grpc_exec_ctx *exec_ctx,
-                                             grpc_call_element *elem) {
-  /* apply service-config level configuration to the call (now that we're
-   * certain it exists) */
+static void create_subchannel_call_locked(grpc_exec_ctx *exec_ctx,
+                                          grpc_call_element *elem,
+                                          grpc_error *error) {
   call_data *calld = elem->call_data;
-  channel_data *chand = elem->channel_data;
-  gpr_timespec per_method_deadline;
-  if (set_call_method_params_from_service_config_locked(exec_ctx, elem,
-                                                        &per_method_deadline)) {
-    // If the deadline from the service config is shorter than the one
-    // from the client API, reset the deadline timer.
-    if (chand->deadline_checking_enabled &&
-        gpr_time_cmp(per_method_deadline, calld->deadline) < 0) {
-      calld->deadline = per_method_deadline;
-      grpc_deadline_state_reset(exec_ctx, elem, calld->deadline);
-    }
+  grpc_subchannel_call *subchannel_call = NULL;
+  const grpc_connected_subchannel_call_args call_args = {
+      .pollent = calld->pollent,
+      .path = calld->path,
+      .start_time = calld->call_start_time,
+      .deadline = calld->deadline,
+      .arena = calld->arena,
+      .context = calld->subchannel_call_context};
+  grpc_error *new_error = grpc_connected_subchannel_create_call(
+      exec_ctx, calld->connected_subchannel, &call_args, &subchannel_call);
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: create subchannel_call=%p: error=%s",
+            elem->channel_data, calld, subchannel_call,
+            grpc_error_string(new_error));
+  }
+  GPR_ASSERT(set_call_or_error(
+      calld, (call_or_error){.subchannel_call = subchannel_call}));
+  if (new_error != GRPC_ERROR_NONE) {
+    new_error = grpc_error_add_child(new_error, error);
+    waiting_for_pick_batches_fail_locked(exec_ctx, elem, new_error);
+  } else {
+    waiting_for_pick_batches_resume_locked(exec_ctx, elem);
   }
+  GRPC_ERROR_UNREF(error);
 }
 
-static void subchannel_ready_locked(grpc_exec_ctx *exec_ctx, void *arg,
+static void subchannel_ready_locked(grpc_exec_ctx *exec_ctx,
+                                    grpc_call_element *elem,
                                     grpc_error *error) {
-  grpc_call_element *elem = arg;
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
-  GPR_ASSERT(calld->pick_pending);
-  calld->pick_pending = false;
   grpc_polling_entity_del_from_pollset_set(exec_ctx, calld->pollent,
                                            chand->interested_parties);
+  call_or_error coe = get_call_or_error(calld);
   if (calld->connected_subchannel == NULL) {
-    gpr_atm_no_barrier_store(&calld->subchannel_call, 1);
-    fail_locked(exec_ctx, calld,
-                GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-                    "Failed to create subchannel", &error, 1));
-  } else if (GET_CALL(calld) == CANCELLED_CALL) {
+    // Failed to create subchannel.
+    grpc_error *failure =
+        error == GRPC_ERROR_NONE
+            ? GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                  "Call dropped by load balancing policy")
+            : GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                  "Failed to create subchannel", &error, 1);
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG,
+              "chand=%p calld=%p: failed to create subchannel: error=%s", chand,
+              calld, grpc_error_string(failure));
+    }
+    set_call_or_error(calld, (call_or_error){.error = GRPC_ERROR_REF(failure)});
+    waiting_for_pick_batches_fail_locked(exec_ctx, elem, failure);
+  } else if (coe.error != GRPC_ERROR_NONE) {
     /* already cancelled before subchannel became ready */
+    grpc_error *child_errors[] = {error, coe.error};
     grpc_error *cancellation_error =
         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-            "Cancelled before creating subchannel", &error, 1);
+            "Cancelled before creating subchannel", child_errors,
+            GPR_ARRAY_SIZE(child_errors));
     /* if due to deadline, attach the deadline exceeded status to the error */
     if (gpr_time_cmp(calld->deadline, gpr_now(GPR_CLOCK_MONOTONIC)) < 0) {
       cancellation_error =
           grpc_error_set_int(cancellation_error, GRPC_ERROR_INT_GRPC_STATUS,
                              GRPC_STATUS_DEADLINE_EXCEEDED);
     }
-    fail_locked(exec_ctx, calld, cancellation_error);
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG,
+              "chand=%p calld=%p: cancelled before subchannel became ready: %s",
+              chand, calld, grpc_error_string(cancellation_error));
+    }
+    waiting_for_pick_batches_fail_locked(exec_ctx, elem, cancellation_error);
   } else {
     /* Create call on subchannel. */
-    grpc_subchannel_call *subchannel_call = NULL;
-    const grpc_connected_subchannel_call_args call_args = {
-        .pollent = calld->pollent,
-        .path = calld->path,
-        .start_time = calld->call_start_time,
-        .deadline = calld->deadline,
-        .arena = calld->arena,
-        .context = calld->subchannel_call_context};
-    grpc_error *new_error = grpc_connected_subchannel_create_call(
-        exec_ctx, calld->connected_subchannel, &call_args, &subchannel_call);
-    gpr_atm_rel_store(&calld->subchannel_call,
-                      (gpr_atm)(uintptr_t)subchannel_call);
-    if (new_error != GRPC_ERROR_NONE) {
-      new_error = grpc_error_add_child(new_error, error);
-      fail_locked(exec_ctx, calld, new_error);
-    } else {
-      retry_waiting_locked(exec_ctx, calld);
-    }
+    create_subchannel_call_locked(exec_ctx, elem, GRPC_ERROR_REF(error));
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel");
+  GRPC_ERROR_UNREF(error);
 }
 
 static char *cc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
   call_data *calld = elem->call_data;
-  grpc_subchannel_call *subchannel_call = GET_CALL(calld);
-  if (subchannel_call == NULL || subchannel_call == CANCELLED_CALL) {
+  grpc_subchannel_call *subchannel_call =
+      get_call_or_error(calld).subchannel_call;
+  if (subchannel_call == NULL) {
     return NULL;
   } else {
     return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call);
   }
 }
 
+/** Return true if subchannel is available immediately (in which case
+    subchannel_ready_locked() should not be called), or false otherwise (in
+    which case subchannel_ready_locked() should be called when the subchannel
+    is available). */
+static bool pick_subchannel_locked(grpc_exec_ctx *exec_ctx,
+                                   grpc_call_element *elem);
+
 typedef struct {
-  grpc_metadata_batch *initial_metadata;
-  uint32_t initial_metadata_flags;
-  grpc_connected_subchannel **connected_subchannel;
-  grpc_call_context_element *subchannel_call_context;
-  grpc_closure *on_ready;
   grpc_call_element *elem;
+  bool cancelled;
   grpc_closure closure;
-} continue_picking_args;
+} pick_after_resolver_result_args;
 
-/** Return true if subchannel is available immediately (in which case on_ready
-    should not be called), or false otherwise (in which case on_ready should be
-    called when the subchannel is available). */
-static bool pick_subchannel_locked(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-    grpc_metadata_batch *initial_metadata, uint32_t initial_metadata_flags,
-    grpc_connected_subchannel **connected_subchannel,
-    grpc_call_context_element *subchannel_call_context, grpc_closure *on_ready);
-
-static void continue_picking_locked(grpc_exec_ctx *exec_ctx, void *arg,
-                                    grpc_error *error) {
-  continue_picking_args *cpa = arg;
-  if (cpa->connected_subchannel == NULL) {
+static void pick_after_resolver_result_done_locked(grpc_exec_ctx *exec_ctx,
+                                                   void *arg,
+                                                   grpc_error *error) {
+  pick_after_resolver_result_args *args = arg;
+  if (args->cancelled) {
     /* cancelled, do nothing */
-  } else if (error != GRPC_ERROR_NONE) {
-    grpc_closure_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_REF(error));
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "call cancelled before resolver result");
+    }
   } else {
-    if (pick_subchannel_locked(exec_ctx, cpa->elem, cpa->initial_metadata,
-                               cpa->initial_metadata_flags,
-                               cpa->connected_subchannel,
-                               cpa->subchannel_call_context, cpa->on_ready)) {
-      grpc_closure_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_NONE);
+    channel_data *chand = args->elem->channel_data;
+    call_data *calld = args->elem->call_data;
+    if (error != GRPC_ERROR_NONE) {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG, "chand=%p calld=%p: resolver failed to return data",
+                chand, calld);
+      }
+      subchannel_ready_locked(exec_ctx, args->elem, GRPC_ERROR_REF(error));
+    } else {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG, "chand=%p calld=%p: resolver returned, doing pick",
+                chand, calld);
+      }
+      if (pick_subchannel_locked(exec_ctx, args->elem)) {
+        subchannel_ready_locked(exec_ctx, args->elem, GRPC_ERROR_NONE);
+      }
     }
   }
-  gpr_free(cpa);
+  gpr_free(args);
 }
 
-static void cancel_pick_locked(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-                               grpc_error *error) {
+static void pick_after_resolver_result_start_locked(grpc_exec_ctx *exec_ctx,
+                                                    grpc_call_element *elem) {
   channel_data *chand = elem->channel_data;
   call_data *calld = elem->call_data;
-  if (chand->lb_policy != NULL) {
-    grpc_lb_policy_cancel_pick_locked(exec_ctx, chand->lb_policy,
-                                      &calld->connected_subchannel,
-                                      GRPC_ERROR_REF(error));
-  }
-  for (grpc_closure *closure = chand->waiting_for_config_closures.head;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG,
+            "chand=%p calld=%p: deferring pick pending resolver result", chand,
+            calld);
+  }
+  pick_after_resolver_result_args *args =
+      (pick_after_resolver_result_args *)gpr_zalloc(sizeof(*args));
+  args->elem = elem;
+  GRPC_CLOSURE_INIT(&args->closure, pick_after_resolver_result_done_locked,
+                    args, grpc_combiner_scheduler(chand->combiner));
+  grpc_closure_list_append(&chand->waiting_for_resolver_result_closures,
+                           &args->closure, GRPC_ERROR_NONE);
+}
+
+static void pick_after_resolver_result_cancel_locked(grpc_exec_ctx *exec_ctx,
+                                                     grpc_call_element *elem,
+                                                     grpc_error *error) {
+  channel_data *chand = elem->channel_data;
+  call_data *calld = elem->call_data;
+  // If we don't yet have a resolver result, then a closure for
+  // pick_after_resolver_result_done_locked() will have been added to
+  // chand->waiting_for_resolver_result_closures, and it may not be invoked
+  // until after this call has been destroyed.  We mark the operation as
+  // cancelled, so that when pick_after_resolver_result_done_locked()
+  // is called, it will be a no-op.  We also immediately invoke
+  // subchannel_ready_locked() to propagate the error back to the caller.
+  for (grpc_closure *closure = chand->waiting_for_resolver_result_closures.head;
        closure != NULL; closure = closure->next_data.next) {
-    continue_picking_args *cpa = closure->cb_arg;
-    if (cpa->connected_subchannel == &calld->connected_subchannel) {
-      cpa->connected_subchannel = NULL;
-      grpc_closure_sched(exec_ctx, cpa->on_ready,
-                         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-                             "Pick cancelled", &error, 1));
+    pick_after_resolver_result_args *args = closure->cb_arg;
+    if (!args->cancelled && args->elem == elem) {
+      if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+        gpr_log(GPR_DEBUG,
+                "chand=%p calld=%p: "
+                "cancelling pick waiting for resolver result",
+                chand, calld);
+      }
+      args->cancelled = true;
+      subchannel_ready_locked(exec_ctx, elem,
+                              GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                                  "Pick cancelled", &error, 1));
     }
   }
   GRPC_ERROR_UNREF(error);
 }
 
-static bool pick_subchannel_locked(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-    grpc_metadata_batch *initial_metadata, uint32_t initial_metadata_flags,
-    grpc_connected_subchannel **connected_subchannel,
-    grpc_call_context_element *subchannel_call_context,
-    grpc_closure *on_ready) {
-  GPR_TIMER_BEGIN("pick_subchannel", 0);
+// Callback invoked by grpc_lb_policy_pick_locked() for async picks.
+// Unrefs the LB policy after invoking subchannel_ready_locked().
+static void pick_callback_done_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                      grpc_error *error) {
+  grpc_call_element *elem = arg;
+  channel_data *chand = elem->channel_data;
+  call_data *calld = elem->call_data;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: pick completed asynchronously",
+            chand, calld);
+  }
+  GPR_ASSERT(calld->lb_policy != NULL);
+  GRPC_LB_POLICY_UNREF(exec_ctx, calld->lb_policy, "pick_subchannel");
+  calld->lb_policy = NULL;
+  subchannel_ready_locked(exec_ctx, elem, GRPC_ERROR_REF(error));
+}
 
+// Takes a ref to chand->lb_policy and calls grpc_lb_policy_pick_locked().
+// If the pick was completed synchronously, unrefs the LB policy and
+// returns true.
+static bool pick_callback_start_locked(grpc_exec_ctx *exec_ctx,
+                                       grpc_call_element *elem,
+                                       const grpc_lb_policy_pick_args *inputs) {
   channel_data *chand = elem->channel_data;
   call_data *calld = elem->call_data;
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: starting pick on lb_policy=%p",
+            chand, calld, chand->lb_policy);
+  }
+  // Keep a ref to the LB policy in calld while the pick is pending.
+  GRPC_LB_POLICY_REF(chand->lb_policy, "pick_subchannel");
+  calld->lb_policy = chand->lb_policy;
+  GRPC_CLOSURE_INIT(&calld->lb_pick_closure, pick_callback_done_locked, elem,
+                    grpc_combiner_scheduler(chand->combiner));
+  const bool pick_done = grpc_lb_policy_pick_locked(
+      exec_ctx, chand->lb_policy, inputs, &calld->connected_subchannel,
+      calld->subchannel_call_context, NULL, &calld->lb_pick_closure);
+  if (pick_done) {
+    /* synchronous grpc_lb_policy_pick call. Unref the LB policy. */
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p calld=%p: pick completed synchronously",
+              chand, calld);
+    }
+    GRPC_LB_POLICY_UNREF(exec_ctx, calld->lb_policy, "pick_subchannel");
+    calld->lb_policy = NULL;
+  }
+  return pick_done;
+}
 
-  GPR_ASSERT(connected_subchannel);
+static void pick_callback_cancel_locked(grpc_exec_ctx *exec_ctx,
+                                        grpc_call_element *elem,
+                                        grpc_error *error) {
+  channel_data *chand = elem->channel_data;
+  call_data *calld = elem->call_data;
+  GPR_ASSERT(calld->lb_policy != NULL);
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: cancelling pick from LB policy %p",
+            chand, calld, calld->lb_policy);
+  }
+  grpc_lb_policy_cancel_pick_locked(exec_ctx, calld->lb_policy,
+                                    &calld->connected_subchannel, error);
+}
 
+static bool pick_subchannel_locked(grpc_exec_ctx *exec_ctx,
+                                   grpc_call_element *elem) {
+  GPR_TIMER_BEGIN("pick_subchannel", 0);
+  channel_data *chand = elem->channel_data;
+  call_data *calld = elem->call_data;
+  bool pick_done = false;
   if (chand->lb_policy != NULL) {
-    apply_final_configuration_locked(exec_ctx, elem);
-    grpc_lb_policy *lb_policy = chand->lb_policy;
-    GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel");
+    apply_service_config_to_call_locked(exec_ctx, elem);
     // If the application explicitly set wait_for_ready, use that.
     // Otherwise, if the service config specified a value for this
     // method, use that.
+    uint32_t initial_metadata_flags =
+        calld->initial_metadata_payload->send_initial_metadata
+            .send_initial_metadata_flags;
     const bool wait_for_ready_set_from_api =
         initial_metadata_flags &
         GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET;
@@ -1058,160 +1241,108 @@ static bool pick_subchannel_locked(
       }
     }
     const grpc_lb_policy_pick_args inputs = {
-        initial_metadata, initial_metadata_flags, &calld->lb_token_mdelem};
-
-    // Wrap the user-provided callback in order to hold a strong reference to
-    // the LB policy for the duration of the pick.
-    wrapped_on_pick_closure_arg *w_on_pick_arg =
-        gpr_zalloc(sizeof(*w_on_pick_arg));
-    grpc_closure_init(&w_on_pick_arg->wrapper_closure,
-                      wrapped_on_pick_closure_cb, w_on_pick_arg,
-                      grpc_schedule_on_exec_ctx);
-    w_on_pick_arg->wrapped_closure = on_ready;
-    GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel_wrapping");
-    w_on_pick_arg->lb_policy = lb_policy;
-    const bool pick_done = grpc_lb_policy_pick_locked(
-        exec_ctx, lb_policy, &inputs, connected_subchannel,
-        subchannel_call_context, NULL, &w_on_pick_arg->wrapper_closure);
-    if (pick_done) {
-      /* synchronous grpc_lb_policy_pick call. Unref the LB policy. */
-      GRPC_LB_POLICY_UNREF(exec_ctx, w_on_pick_arg->lb_policy,
-                           "pick_subchannel_wrapping");
-      gpr_free(w_on_pick_arg);
+        calld->initial_metadata_payload->send_initial_metadata
+            .send_initial_metadata,
+        initial_metadata_flags, &calld->lb_token_mdelem};
+    pick_done = pick_callback_start_locked(exec_ctx, elem, &inputs);
+  } else if (chand->resolver != NULL) {
+    if (!chand->started_resolving) {
+      start_resolving_locked(exec_ctx, chand);
     }
-    GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "pick_subchannel");
-    GPR_TIMER_END("pick_subchannel", 0);
-    return pick_done;
-  }
-  if (chand->resolver != NULL && !chand->started_resolving) {
-    chand->started_resolving = true;
-    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
-    grpc_resolver_next_locked(exec_ctx, chand->resolver,
-                              &chand->resolver_result,
-                              &chand->on_resolver_result_changed);
-  }
-  if (chand->resolver != NULL) {
-    continue_picking_args *cpa = gpr_malloc(sizeof(*cpa));
-    cpa->initial_metadata = initial_metadata;
-    cpa->initial_metadata_flags = initial_metadata_flags;
-    cpa->connected_subchannel = connected_subchannel;
-    cpa->subchannel_call_context = subchannel_call_context;
-    cpa->on_ready = on_ready;
-    cpa->elem = elem;
-    grpc_closure_init(&cpa->closure, continue_picking_locked, cpa,
-                      grpc_combiner_scheduler(chand->combiner, true));
-    grpc_closure_list_append(&chand->waiting_for_config_closures, &cpa->closure,
-                             GRPC_ERROR_NONE);
+    pick_after_resolver_result_start_locked(exec_ctx, elem);
   } else {
-    grpc_closure_sched(exec_ctx, on_ready,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
+    subchannel_ready_locked(
+        exec_ctx, elem, GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
   }
-
   GPR_TIMER_END("pick_subchannel", 0);
-  return false;
+  return pick_done;
 }
 
-static void start_transport_stream_op_batch_locked_inner(
-    grpc_exec_ctx *exec_ctx, grpc_transport_stream_op_batch *op,
-    grpc_call_element *elem) {
-  channel_data *chand = elem->channel_data;
+static void start_transport_stream_op_batch_locked(grpc_exec_ctx *exec_ctx,
+                                                   void *arg,
+                                                   grpc_error *error_ignored) {
+  GPR_TIMER_BEGIN("start_transport_stream_op_batch_locked", 0);
+  grpc_transport_stream_op_batch *batch = arg;
+  grpc_call_element *elem = batch->handler_private.extra_arg;
   call_data *calld = elem->call_data;
-  grpc_subchannel_call *call;
-
+  channel_data *chand = elem->channel_data;
   /* need to recheck that another thread hasn't set the call */
-  call = GET_CALL(calld);
-  if (call == CANCELLED_CALL) {
+  call_or_error coe = get_call_or_error(calld);
+  if (coe.error != GRPC_ERROR_NONE) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p calld=%p: failing batch with error: %s",
+              chand, calld, grpc_error_string(coe.error));
+    }
     grpc_transport_stream_op_batch_finish_with_failure(
-        exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error));
-    /* early out */
-    return;
-  }
-  if (call != NULL) {
-    grpc_subchannel_call_process_op(exec_ctx, call, op);
-    /* early out */
-    return;
-  }
-  /* if this is a cancellation, then we can raise our cancelled flag */
-  if (op->cancel_stream) {
-    if (!gpr_atm_rel_cas(&calld->subchannel_call, 0,
-                         (gpr_atm)(uintptr_t)CANCELLED_CALL)) {
-      /* recurse to retry */
-      start_transport_stream_op_batch_locked_inner(exec_ctx, op, elem);
-      /* early out */
-      return;
+        exec_ctx, batch, GRPC_ERROR_REF(coe.error));
+    goto done;
+  }
+  if (coe.subchannel_call != NULL) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG,
+              "chand=%p calld=%p: sending batch to subchannel_call=%p", chand,
+              calld, coe.subchannel_call);
+    }
+    grpc_subchannel_call_process_op(exec_ctx, coe.subchannel_call, batch);
+    goto done;
+  }
+  // Add to waiting-for-pick list.  If we succeed in getting a
+  // subchannel call below, we'll handle this batch (along with any
+  // other waiting batches) in waiting_for_pick_batches_resume_locked().
+  waiting_for_pick_batches_add_locked(calld, batch);
+  // If this is a cancellation, cancel the pending pick (if any) and
+  // fail any pending batches.
+  if (batch->cancel_stream) {
+    grpc_error *error = batch->payload->cancel_stream.cancel_error;
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p calld=%p: recording cancel_error=%s", chand,
+              calld, grpc_error_string(error));
+    }
+    /* Stash a copy of cancel_error in our call data, so that we can use
+       it for subsequent operations.  This ensures that if the call is
+       cancelled before any batches are passed down (e.g., if the deadline
+       is in the past when the call starts), we can return the right
+       error to the caller when the first batch does get passed down. */
+    set_call_or_error(calld, (call_or_error){.error = GRPC_ERROR_REF(error)});
+    if (calld->lb_policy != NULL) {
+      pick_callback_cancel_locked(exec_ctx, elem, GRPC_ERROR_REF(error));
     } else {
-      /* Stash a copy of cancel_error in our call data, so that we can use
-         it for subsequent operations.  This ensures that if the call is
-         cancelled before any ops are passed down (e.g., if the deadline
-         is in the past when the call starts), we can return the right
-         error to the caller when the first op does get passed down. */
-      calld->cancel_error =
-          GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error);
-      if (calld->pick_pending) {
-        cancel_pick_locked(
-            exec_ctx, elem,
-            GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error));
-      } else {
-        fail_locked(exec_ctx, calld,
-                    GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error));
-      }
-      grpc_transport_stream_op_batch_finish_with_failure(
-          exec_ctx, op,
-          GRPC_ERROR_REF(op->payload->cancel_stream.cancel_error));
-      /* early out */
-      return;
+      pick_after_resolver_result_cancel_locked(exec_ctx, elem,
+                                               GRPC_ERROR_REF(error));
     }
+    waiting_for_pick_batches_fail_locked(exec_ctx, elem, GRPC_ERROR_REF(error));
+    goto done;
   }
   /* if we don't have a subchannel, try to get one */
-  if (!calld->pick_pending && calld->connected_subchannel == NULL &&
-      op->send_initial_metadata) {
-    calld->pick_pending = true;
-    grpc_closure_init(&calld->next_step, subchannel_ready_locked, elem,
-                      grpc_combiner_scheduler(chand->combiner, true));
+  if (batch->send_initial_metadata) {
+    GPR_ASSERT(calld->connected_subchannel == NULL);
+    calld->initial_metadata_payload = batch->payload;
     GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel");
     /* If a subchannel is not available immediately, the polling entity from
        call_data should be provided to channel_data's interested_parties, so
        that IO of the lb_policy and resolver could be done under it. */
-    if (pick_subchannel_locked(
-            exec_ctx, elem,
-            op->payload->send_initial_metadata.send_initial_metadata,
-            op->payload->send_initial_metadata.send_initial_metadata_flags,
-            &calld->connected_subchannel, calld->subchannel_call_context,
-            &calld->next_step)) {
-      calld->pick_pending = false;
+    if (pick_subchannel_locked(exec_ctx, elem)) {
+      // Pick was returned synchronously.
       GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel");
+      if (calld->connected_subchannel == NULL) {
+        grpc_error *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+            "Call dropped by load balancing policy");
+        set_call_or_error(calld,
+                          (call_or_error){.error = GRPC_ERROR_REF(error)});
+        waiting_for_pick_batches_fail_locked(exec_ctx, elem, error);
+      } else {
+        // Create subchannel call.
+        create_subchannel_call_locked(exec_ctx, elem, GRPC_ERROR_NONE);
+      }
     } else {
       grpc_polling_entity_add_to_pollset_set(exec_ctx, calld->pollent,
                                              chand->interested_parties);
     }
   }
-  /* if we've got a subchannel, then let's ask it to create a call */
-  if (!calld->pick_pending && calld->connected_subchannel != NULL) {
-    grpc_subchannel_call *subchannel_call = NULL;
-    const grpc_connected_subchannel_call_args call_args = {
-        .pollent = calld->pollent,
-        .path = calld->path,
-        .start_time = calld->call_start_time,
-        .deadline = calld->deadline,
-        .arena = calld->arena,
-        .context = calld->subchannel_call_context};
-    grpc_error *error = grpc_connected_subchannel_create_call(
-        exec_ctx, calld->connected_subchannel, &call_args, &subchannel_call);
-    gpr_atm_rel_store(&calld->subchannel_call,
-                      (gpr_atm)(uintptr_t)subchannel_call);
-    if (error != GRPC_ERROR_NONE) {
-      fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error));
-      grpc_transport_stream_op_batch_finish_with_failure(exec_ctx, op, error);
-    } else {
-      retry_waiting_locked(exec_ctx, calld);
-      /* recurse to retry */
-      start_transport_stream_op_batch_locked_inner(exec_ctx, op, elem);
-    }
-    /* early out */
-    return;
-  }
-  /* nothing to be done but wait */
-  add_waiting_locked(calld, op);
+done:
+  GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call,
+                        "start_transport_stream_op_batch");
+  GPR_TIMER_END("start_transport_stream_op_batch_locked", 0);
 }
 
 static void on_complete(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
@@ -1230,34 +1361,10 @@ static void on_complete(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
           calld->retry_throttle_data);
     }
   }
-  grpc_closure_run(exec_ctx, calld->original_on_complete,
+  GRPC_CLOSURE_RUN(exec_ctx, calld->original_on_complete,
                    GRPC_ERROR_REF(error));
 }
 
-static void start_transport_stream_op_batch_locked(grpc_exec_ctx *exec_ctx,
-                                                   void *arg,
-                                                   grpc_error *error_ignored) {
-  GPR_TIMER_BEGIN("start_transport_stream_op_batch_locked", 0);
-
-  grpc_transport_stream_op_batch *op = arg;
-  grpc_call_element *elem = op->handler_private.extra_arg;
-  call_data *calld = elem->call_data;
-
-  if (op->recv_trailing_metadata) {
-    GPR_ASSERT(op->on_complete != NULL);
-    calld->original_on_complete = op->on_complete;
-    grpc_closure_init(&calld->on_complete, on_complete, elem,
-                      grpc_schedule_on_exec_ctx);
-    op->on_complete = &calld->on_complete;
-  }
-
-  start_transport_stream_op_batch_locked_inner(exec_ctx, op, elem);
-
-  GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call,
-                        "start_transport_stream_op_batch");
-  GPR_TIMER_END("start_transport_stream_op_batch_locked", 0);
-}
-
 /* The logic here is fairly complicated, due to (a) the fact that we
    need to handle the case where we receive the send op before the
    initial metadata op, and (b) the need for efficiency, especially in
@@ -1268,39 +1375,59 @@ static void start_transport_stream_op_batch_locked(grpc_exec_ctx *exec_ctx,
    If it has, we proceed on the fast path. */
 static void cc_start_transport_stream_op_batch(
     grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-    grpc_transport_stream_op_batch *op) {
+    grpc_transport_stream_op_batch *batch) {
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
-  GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
+  if (GRPC_TRACER_ON(grpc_client_channel_trace) ||
+      GRPC_TRACER_ON(grpc_trace_channel)) {
+    grpc_call_log_op(GPR_INFO, elem, batch);
+  }
   if (chand->deadline_checking_enabled) {
     grpc_deadline_state_client_start_transport_stream_op_batch(exec_ctx, elem,
-                                                               op);
+                                                               batch);
+  }
+  // Intercept on_complete for recv_trailing_metadata so that we can
+  // check retry throttle status.
+  if (batch->recv_trailing_metadata) {
+    GPR_ASSERT(batch->on_complete != NULL);
+    calld->original_on_complete = batch->on_complete;
+    GRPC_CLOSURE_INIT(&calld->on_complete, on_complete, elem,
+                      grpc_schedule_on_exec_ctx);
+    batch->on_complete = &calld->on_complete;
   }
   /* try to (atomically) get the call */
-  grpc_subchannel_call *call = GET_CALL(calld);
+  call_or_error coe = get_call_or_error(calld);
   GPR_TIMER_BEGIN("cc_start_transport_stream_op_batch", 0);
-  if (call == CANCELLED_CALL) {
+  if (coe.error != GRPC_ERROR_NONE) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG, "chand=%p calld=%p: failing batch with error: %s",
+              chand, calld, grpc_error_string(coe.error));
+    }
     grpc_transport_stream_op_batch_finish_with_failure(
-        exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error));
-    GPR_TIMER_END("cc_start_transport_stream_op_batch", 0);
-    /* early out */
-    return;
-  }
-  if (call != NULL) {
-    grpc_subchannel_call_process_op(exec_ctx, call, op);
-    GPR_TIMER_END("cc_start_transport_stream_op_batch", 0);
-    /* early out */
-    return;
+        exec_ctx, batch, GRPC_ERROR_REF(coe.error));
+    goto done;
+  }
+  if (coe.subchannel_call != NULL) {
+    if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+      gpr_log(GPR_DEBUG,
+              "chand=%p calld=%p: sending batch to subchannel_call=%p", chand,
+              calld, coe.subchannel_call);
+    }
+    grpc_subchannel_call_process_op(exec_ctx, coe.subchannel_call, batch);
+    goto done;
   }
   /* we failed; lock and figure out what to do */
+  if (GRPC_TRACER_ON(grpc_client_channel_trace)) {
+    gpr_log(GPR_DEBUG, "chand=%p calld=%p: entering combiner", chand, calld);
+  }
   GRPC_CALL_STACK_REF(calld->owning_call, "start_transport_stream_op_batch");
-  op->handler_private.extra_arg = elem;
-  grpc_closure_sched(
-      exec_ctx,
-      grpc_closure_init(&op->handler_private.closure,
-                        start_transport_stream_op_batch_locked, op,
-                        grpc_combiner_scheduler(chand->combiner, false)),
+  batch->handler_private.extra_arg = elem;
+  GRPC_CLOSURE_SCHED(
+      exec_ctx, GRPC_CLOSURE_INIT(&batch->handler_private.closure,
+                                  start_transport_stream_op_batch_locked, batch,
+                                  grpc_combiner_scheduler(chand->combiner)),
       GRPC_ERROR_NONE);
+done:
   GPR_TIMER_END("cc_start_transport_stream_op_batch", 0);
 }
 
@@ -1336,15 +1463,17 @@ static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx,
   if (calld->method_params != NULL) {
     method_parameters_unref(calld->method_params);
   }
-  GRPC_ERROR_UNREF(calld->cancel_error);
-  grpc_subchannel_call *call = GET_CALL(calld);
-  if (call != NULL && call != CANCELLED_CALL) {
-    grpc_subchannel_call_set_cleanup_closure(call, then_schedule_closure);
+  call_or_error coe = get_call_or_error(calld);
+  GRPC_ERROR_UNREF(coe.error);
+  if (coe.subchannel_call != NULL) {
+    grpc_subchannel_call_set_cleanup_closure(coe.subchannel_call,
+                                             then_schedule_closure);
     then_schedule_closure = NULL;
-    GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, call, "client_channel_destroy_call");
+    GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, coe.subchannel_call,
+                               "client_channel_destroy_call");
   }
-  GPR_ASSERT(!calld->pick_pending);
-  GPR_ASSERT(calld->waiting_ops_count == 0);
+  GPR_ASSERT(calld->lb_policy == NULL);
+  GPR_ASSERT(calld->waiting_for_pick_batches_count == 0);
   if (calld->connected_subchannel != NULL) {
     GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, calld->connected_subchannel,
                                     "picked");
@@ -1355,8 +1484,7 @@ static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx,
           calld->subchannel_call_context[i].value);
     }
   }
-  gpr_free(calld->waiting_ops);
-  grpc_closure_sched(exec_ctx, then_schedule_closure, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx, then_schedule_closure, GRPC_ERROR_NONE);
 }
 
 static void cc_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
@@ -1393,11 +1521,7 @@ static void try_to_connect_locked(grpc_exec_ctx *exec_ctx, void *arg,
   } else {
     chand->exit_idle_when_lb_policy_arrives = true;
     if (!chand->started_resolving && chand->resolver != NULL) {
-      GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
-      chand->started_resolving = true;
-      grpc_resolver_next_locked(exec_ctx, chand->resolver,
-                                &chand->resolver_result,
-                                &chand->on_resolver_result_changed);
+      start_resolving_locked(exec_ctx, chand);
     }
   }
   GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "try_to_connect");
@@ -1410,59 +1534,145 @@ grpc_connectivity_state grpc_client_channel_check_connectivity_state(
       grpc_connectivity_state_check(&chand->state_tracker);
   if (out == GRPC_CHANNEL_IDLE && try_to_connect) {
     GRPC_CHANNEL_STACK_REF(chand->owning_stack, "try_to_connect");
-    grpc_closure_sched(
-        exec_ctx,
-        grpc_closure_create(try_to_connect_locked, chand,
-                            grpc_combiner_scheduler(chand->combiner, false)),
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, GRPC_CLOSURE_CREATE(try_to_connect_locked, chand,
+                                      grpc_combiner_scheduler(chand->combiner)),
         GRPC_ERROR_NONE);
   }
   return out;
 }
 
-typedef struct {
+typedef struct external_connectivity_watcher {
   channel_data *chand;
-  grpc_pollset *pollset;
+  grpc_polling_entity pollent;
   grpc_closure *on_complete;
+  grpc_closure *watcher_timer_init;
   grpc_connectivity_state *state;
   grpc_closure my_closure;
+  struct external_connectivity_watcher *next;
 } external_connectivity_watcher;
 
+static external_connectivity_watcher *lookup_external_connectivity_watcher(
+    channel_data *chand, grpc_closure *on_complete) {
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL && w->on_complete != on_complete) {
+    w = w->next;
+  }
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+  return w;
+}
+
+static void external_connectivity_watcher_list_append(
+    channel_data *chand, external_connectivity_watcher *w) {
+  GPR_ASSERT(!lookup_external_connectivity_watcher(chand, w->on_complete));
+
+  gpr_mu_lock(&w->chand->external_connectivity_watcher_list_mu);
+  GPR_ASSERT(!w->next);
+  w->next = chand->external_connectivity_watcher_list_head;
+  chand->external_connectivity_watcher_list_head = w;
+  gpr_mu_unlock(&w->chand->external_connectivity_watcher_list_mu);
+}
+
+static void external_connectivity_watcher_list_remove(
+    channel_data *chand, external_connectivity_watcher *too_remove) {
+  GPR_ASSERT(
+      lookup_external_connectivity_watcher(chand, too_remove->on_complete));
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  if (too_remove == chand->external_connectivity_watcher_list_head) {
+    chand->external_connectivity_watcher_list_head = too_remove->next;
+    gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+    return;
+  }
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL) {
+    if (w->next == too_remove) {
+      w->next = w->next->next;
+      gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+      return;
+    }
+    w = w->next;
+  }
+  GPR_UNREACHABLE_CODE(return );
+}
+
+int grpc_client_channel_num_external_connectivity_watchers(
+    grpc_channel_element *elem) {
+  channel_data *chand = elem->channel_data;
+  int count = 0;
+
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL) {
+    count++;
+    w = w->next;
+  }
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+
+  return count;
+}
+
 static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg,
                                        grpc_error *error) {
   external_connectivity_watcher *w = arg;
   grpc_closure *follow_up = w->on_complete;
-  grpc_pollset_set_del_pollset(exec_ctx, w->chand->interested_parties,
-                               w->pollset);
+  grpc_polling_entity_del_from_pollset_set(exec_ctx, &w->pollent,
+                                           w->chand->interested_parties);
   GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack,
                            "external_connectivity_watcher");
+  external_connectivity_watcher_list_remove(w->chand, w);
   gpr_free(w);
-  grpc_closure_run(exec_ctx, follow_up, GRPC_ERROR_REF(error));
+  GRPC_CLOSURE_RUN(exec_ctx, follow_up, GRPC_ERROR_REF(error));
 }
 
 static void watch_connectivity_state_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                             grpc_error *error_ignored) {
   external_connectivity_watcher *w = arg;
-  grpc_closure_init(&w->my_closure, on_external_watch_complete, w,
-                    grpc_schedule_on_exec_ctx);
-  grpc_connectivity_state_notify_on_state_change(
-      exec_ctx, &w->chand->state_tracker, w->state, &w->my_closure);
+  external_connectivity_watcher *found = NULL;
+  if (w->state != NULL) {
+    external_connectivity_watcher_list_append(w->chand, w);
+    GRPC_CLOSURE_RUN(exec_ctx, w->watcher_timer_init, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_INIT(&w->my_closure, on_external_watch_complete, w,
+                      grpc_schedule_on_exec_ctx);
+    grpc_connectivity_state_notify_on_state_change(
+        exec_ctx, &w->chand->state_tracker, w->state, &w->my_closure);
+  } else {
+    GPR_ASSERT(w->watcher_timer_init == NULL);
+    found = lookup_external_connectivity_watcher(w->chand, w->on_complete);
+    if (found) {
+      GPR_ASSERT(found->on_complete == w->on_complete);
+      grpc_connectivity_state_notify_on_state_change(
+          exec_ctx, &found->chand->state_tracker, NULL, &found->my_closure);
+    }
+    grpc_polling_entity_del_from_pollset_set(exec_ctx, &w->pollent,
+                                             w->chand->interested_parties);
+    GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack,
+                             "external_connectivity_watcher");
+    gpr_free(w);
+  }
 }
 
 void grpc_client_channel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
-    grpc_connectivity_state *state, grpc_closure *closure) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_polling_entity pollent, grpc_connectivity_state *state,
+    grpc_closure *closure, grpc_closure *watcher_timer_init) {
   channel_data *chand = elem->channel_data;
-  external_connectivity_watcher *w = gpr_malloc(sizeof(*w));
+  external_connectivity_watcher *w = gpr_zalloc(sizeof(*w));
   w->chand = chand;
-  w->pollset = pollset;
+  w->pollent = pollent;
   w->on_complete = closure;
   w->state = state;
-  grpc_pollset_set_add_pollset(exec_ctx, chand->interested_parties, pollset);
+  w->watcher_timer_init = watcher_timer_init;
+  grpc_polling_entity_add_to_pollset_set(exec_ctx, &w->pollent,
+                                         chand->interested_parties);
   GRPC_CHANNEL_STACK_REF(w->chand->owning_stack,
                          "external_connectivity_watcher");
-  grpc_closure_sched(
+  GRPC_CLOSURE_SCHED(
       exec_ctx,
-      grpc_closure_init(&w->my_closure, watch_connectivity_state_locked, w,
-                        grpc_combiner_scheduler(chand->combiner, true)),
+      GRPC_CLOSURE_INIT(&w->my_closure, watch_connectivity_state_locked, w,
+                        grpc_combiner_scheduler(chand->combiner)),
       GRPC_ERROR_NONE);
 }
diff --git a/src/core/ext/filters/client_channel/client_channel.h b/src/core/ext/filters/client_channel/client_channel.h
index 8d2490ea55..c99f0092e9 100644
--- a/src/core/ext/filters/client_channel/client_channel.h
+++ b/src/core/ext/filters/client_channel/client_channel.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -38,6 +23,8 @@
 #include "src/core/ext/filters/client_channel/resolver.h"
 #include "src/core/lib/channel/channel_stack.h"
 
+extern grpc_tracer_flag grpc_client_channel_trace;
+
 // Channel arg key for server URI string.
 #define GRPC_ARG_SERVER_URI "grpc.server_uri"
 
@@ -53,9 +40,13 @@ extern const grpc_channel_filter grpc_client_channel_filter;
 grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect);
 
+int grpc_client_channel_num_external_connectivity_watchers(
+    grpc_channel_element *elem);
+
 void grpc_client_channel_watch_connectivity_state(
-    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
-    grpc_connectivity_state *state, grpc_closure *on_complete);
+    grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
+    grpc_polling_entity pollent, grpc_connectivity_state *state,
+    grpc_closure *on_complete, grpc_closure *watcher_timer_init);
 
 /* Debug helper: pull the subchannel call from a call stack element */
 grpc_subchannel_call *grpc_client_channel_get_subchannel_call(
diff --git a/src/core/ext/filters/client_channel/client_channel_factory.c b/src/core/ext/filters/client_channel/client_channel_factory.c
index 44e83b54b5..7220a8639e 100644
--- a/src/core/ext/filters/client_channel/client_channel_factory.c
+++ b/src/core/ext/filters/client_channel/client_channel_factory.c
@@ -1,37 +1,23 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 #include "src/core/ext/filters/client_channel/client_channel_factory.h"
+#include "src/core/lib/channel/channel_args.h"
 
 void grpc_client_channel_factory_ref(grpc_client_channel_factory* factory) {
   factory->vtable->ref(factory);
@@ -78,10 +64,6 @@ static const grpc_arg_pointer_vtable factory_arg_vtable = {
 
 grpc_arg grpc_client_channel_factory_create_channel_arg(
     grpc_client_channel_factory* factory) {
-  grpc_arg arg;
-  arg.type = GRPC_ARG_POINTER;
-  arg.key = GRPC_ARG_CLIENT_CHANNEL_FACTORY;
-  arg.value.pointer.p = factory;
-  arg.value.pointer.vtable = &factory_arg_vtable;
-  return arg;
+  return grpc_channel_arg_pointer_create(GRPC_ARG_CLIENT_CHANNEL_FACTORY,
+                                         factory, &factory_arg_vtable);
 }
diff --git a/src/core/ext/filters/client_channel/client_channel_factory.h b/src/core/ext/filters/client_channel/client_channel_factory.h
index 2355588f18..ce6266c769 100644
--- a/src/core/ext/filters/client_channel/client_channel_factory.h
+++ b/src/core/ext/filters/client_channel/client_channel_factory.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/client_channel_plugin.c b/src/core/ext/filters/client_channel/client_channel_plugin.c
index 0e3eae6615..c32e83d012 100644
--- a/src/core/ext/filters/client_channel/client_channel_plugin.c
+++ b/src/core/ext/filters/client_channel/client_channel_plugin.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -69,10 +54,8 @@ static bool set_default_host_if_unset(grpc_exec_ctx *exec_ctx,
   char *default_authority = grpc_get_default_authority(
       exec_ctx, grpc_channel_stack_builder_get_target(builder));
   if (default_authority != NULL) {
-    grpc_arg arg;
-    arg.type = GRPC_ARG_STRING;
-    arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
-    arg.value.string = default_authority;
+    grpc_arg arg = grpc_channel_arg_string_create(GRPC_ARG_DEFAULT_AUTHORITY,
+                                                  default_authority);
     grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
     grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
                                                      new_args);
@@ -95,6 +78,10 @@ void grpc_client_channel_init(void) {
       GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY, append_filter,
       (void *)&grpc_client_channel_filter);
   grpc_http_connect_register_handshaker_factory();
+  grpc_register_tracer(&grpc_client_channel_trace);
+#ifndef NDEBUG
+  grpc_register_tracer(&grpc_trace_resolver_refcount);
+#endif
 }
 
 void grpc_client_channel_shutdown(void) {
diff --git a/src/core/ext/filters/client_channel/connector.c b/src/core/ext/filters/client_channel/connector.c
index 51c1d7ece7..c258468e58 100644
--- a/src/core/ext/filters/client_channel/connector.c
+++ b/src/core/ext/filters/client_channel/connector.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/connector.h b/src/core/ext/filters/client_channel/connector.h
index 23040c3e23..7f3d4a1cc0 100644
--- a/src/core/ext/filters/client_channel/connector.h
+++ b/src/core/ext/filters/client_channel/connector.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/http_connect_handshaker.c b/src/core/ext/filters/client_channel/http_connect_handshaker.c
index c09a863d00..0952dc6d4e 100644
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.c
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -133,7 +118,7 @@ static void handshake_failed_locked(grpc_exec_ctx* exec_ctx,
     handshaker->shutdown = true;
   }
   // Invoke callback.
-  grpc_closure_sched(exec_ctx, handshaker->on_handshake_done, error);
+  GRPC_CLOSURE_SCHED(exec_ctx, handshaker->on_handshake_done, error);
 }
 
 // Callback invoked when finished writing HTTP CONNECT request.
@@ -232,7 +217,7 @@ static void on_read_done(grpc_exec_ctx* exec_ctx, void* arg,
     goto done;
   }
   // Success.  Invoke handshake-done callback.
-  grpc_closure_sched(exec_ctx, handshaker->on_handshake_done, error);
+  GRPC_CLOSURE_SCHED(exec_ctx, handshaker->on_handshake_done, error);
 done:
   // Set shutdown to true so that subsequent calls to
   // http_connect_handshaker_shutdown() do nothing.
@@ -281,7 +266,7 @@ static void http_connect_handshaker_do_handshake(
     gpr_mu_lock(&handshaker->mu);
     handshaker->shutdown = true;
     gpr_mu_unlock(&handshaker->mu);
-    grpc_closure_sched(exec_ctx, on_handshake_done, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, on_handshake_done, GRPC_ERROR_NONE);
     return;
   }
   GPR_ASSERT(arg->type == GRPC_ARG_STRING);
@@ -354,9 +339,9 @@ static grpc_handshaker* grpc_http_connect_handshaker_create() {
   gpr_mu_init(&handshaker->mu);
   gpr_ref_init(&handshaker->refcount, 1);
   grpc_slice_buffer_init(&handshaker->write_buffer);
-  grpc_closure_init(&handshaker->request_done_closure, on_write_done,
+  GRPC_CLOSURE_INIT(&handshaker->request_done_closure, on_write_done,
                     handshaker, grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&handshaker->response_read_closure, on_read_done,
+  GRPC_CLOSURE_INIT(&handshaker->response_read_closure, on_read_done,
                     handshaker, grpc_schedule_on_exec_ctx);
   grpc_http_parser_init(&handshaker->http_parser, GRPC_HTTP_RESPONSE,
                         &handshaker->http_response);
diff --git a/src/core/ext/filters/client_channel/http_connect_handshaker.h b/src/core/ext/filters/client_channel/http_connect_handshaker.h
index 6d7c204d71..928a23dc93 100644
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.h
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/http_proxy.c b/src/core/ext/filters/client_channel/http_proxy.c
index f8a2d06b8a..cfb5ec6f00 100644
--- a/src/core/ext/filters/client_channel/http_proxy.c
+++ b/src/core/ext/filters/client_channel/http_proxy.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -95,10 +80,9 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
     grpc_uri_destroy(uri);
     return false;
   }
-  grpc_arg new_arg;
-  new_arg.key = GRPC_ARG_HTTP_CONNECT_SERVER;
-  new_arg.type = GRPC_ARG_STRING;
-  new_arg.value.string = uri->path[0] == '/' ? uri->path + 1 : uri->path;
+  grpc_arg new_arg = grpc_channel_arg_string_create(
+      GRPC_ARG_HTTP_CONNECT_SERVER,
+      uri->path[0] == '/' ? uri->path + 1 : uri->path);
   *new_args = grpc_channel_args_copy_and_add(args, &new_arg, 1);
   grpc_uri_destroy(uri);
   return true;
diff --git a/src/core/ext/filters/client_channel/http_proxy.h b/src/core/ext/filters/client_channel/http_proxy.h
index f0df74bbda..34694931d0 100644
--- a/src/core/ext/filters/client_channel/http_proxy.h
+++ b/src/core/ext/filters/client_channel/http_proxy.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy.c b/src/core/ext/filters/client_channel/lb_policy.c
index 112ba40658..10b032214b 100644
--- a/src/core/ext/filters/client_channel/lb_policy.c
+++ b/src/core/ext/filters/client_channel/lb_policy.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -36,6 +21,11 @@
 
 #define WEAK_REF_BITS 16
 
+#ifndef NDEBUG
+grpc_tracer_flag grpc_trace_lb_policy_refcount =
+    GRPC_TRACER_INITIALIZER(false, "lb_policy_refcount");
+#endif
+
 void grpc_lb_policy_init(grpc_lb_policy *policy,
                          const grpc_lb_policy_vtable *vtable,
                          grpc_combiner *combiner) {
@@ -45,7 +35,7 @@ void grpc_lb_policy_init(grpc_lb_policy *policy,
   policy->combiner = GRPC_COMBINER_REF(combiner, "lb_policy");
 }
 
-#ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
+#ifndef NDEBUG
 #define REF_FUNC_EXTRA_ARGS , const char *file, int line, const char *reason
 #define REF_MUTATE_EXTRA_ARGS REF_FUNC_EXTRA_ARGS, const char *purpose
 #define REF_FUNC_PASS_ARGS(new_reason) , file, line, new_reason
@@ -61,11 +51,12 @@ static gpr_atm ref_mutate(grpc_lb_policy *c, gpr_atm delta,
                           int barrier REF_MUTATE_EXTRA_ARGS) {
   gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
                             : gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
-#ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
-          "LB_POLICY: 0x%" PRIxPTR " %12s 0x%" PRIxPTR " -> 0x%" PRIxPTR
-          " [%s]",
-          (intptr_t)c, purpose, old_val, old_val + delta, reason);
+#ifndef NDEBUG
+  if (GRPC_TRACER_ON(grpc_trace_lb_policy_refcount)) {
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "LB_POLICY: 0x%p %12s 0x%" PRIxPTR " -> 0x%" PRIxPTR " [%s]", c,
+            purpose, old_val, old_val + delta, reason);
+  }
 #endif
   return old_val;
 }
@@ -89,11 +80,10 @@ void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx,
   gpr_atm mask = ~(gpr_atm)((1 << WEAK_REF_BITS) - 1);
   gpr_atm check = 1 << WEAK_REF_BITS;
   if ((old_val & mask) == check) {
-    grpc_closure_sched(
-        exec_ctx,
-        grpc_closure_create(shutdown_locked, policy,
-                            grpc_combiner_scheduler(policy->combiner, false)),
-        GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, GRPC_CLOSURE_CREATE(
+                                     shutdown_locked, policy,
+                                     grpc_combiner_scheduler(policy->combiner)),
+                       GRPC_ERROR_NONE);
   } else {
     grpc_lb_policy_weak_unref(exec_ctx,
                               policy REF_FUNC_PASS_ARGS("strong-unref"));
@@ -166,3 +156,9 @@ grpc_connectivity_state grpc_lb_policy_check_connectivity_locked(
   return policy->vtable->check_connectivity_locked(exec_ctx, policy,
                                                    connectivity_error);
 }
+
+void grpc_lb_policy_update_locked(grpc_exec_ctx *exec_ctx,
+                                  grpc_lb_policy *policy,
+                                  const grpc_lb_policy_args *lb_policy_args) {
+  policy->vtable->update_locked(exec_ctx, policy, lb_policy_args);
+}
diff --git a/src/core/ext/filters/client_channel/lb_policy.h b/src/core/ext/filters/client_channel/lb_policy.h
index 184b2ef720..645d51e138 100644
--- a/src/core/ext/filters/client_channel/lb_policy.h
+++ b/src/core/ext/filters/client_channel/lb_policy.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -42,6 +27,11 @@
     is expected to be extended to contain some parameters) */
 typedef struct grpc_lb_policy grpc_lb_policy;
 typedef struct grpc_lb_policy_vtable grpc_lb_policy_vtable;
+typedef struct grpc_lb_policy_args grpc_lb_policy_args;
+
+#ifndef NDEBUG
+extern grpc_tracer_flag grpc_trace_lb_policy_refcount;
+#endif
 
 struct grpc_lb_policy {
   const grpc_lb_policy_vtable *vtable;
@@ -105,10 +95,12 @@ struct grpc_lb_policy_vtable {
                                         grpc_lb_policy *policy,
                                         grpc_connectivity_state *state,
                                         grpc_closure *closure);
+
+  void (*update_locked)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                        const grpc_lb_policy_args *args);
 };
 
-/*#define GRPC_LB_POLICY_REFCOUNT_DEBUG*/
-#ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG
+#ifndef NDEBUG
 
 /* Strong references: the policy will shutdown when they reach zero */
 #define GRPC_LB_POLICY_REF(p, r) \
@@ -149,7 +141,9 @@ void grpc_lb_policy_init(grpc_lb_policy *policy,
 
 /** Finds an appropriate subchannel for a call, based on \a pick_args.
 
-    \a target will be set to the selected subchannel, or NULL on failure.
+    \a target will be set to the selected subchannel, or NULL on failure
+    or when the LB policy decides to drop the call.
+
     Upon success, \a user_data will be set to whatever opaque information
     may need to be propagated from the LB policy, or NULL if not needed.
     \a context will be populated with context to pass to the subchannel
@@ -205,4 +199,9 @@ grpc_connectivity_state grpc_lb_policy_check_connectivity_locked(
     grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
     grpc_error **connectivity_error);
 
+/** Update \a policy with \a lb_policy_args. */
+void grpc_lb_policy_update_locked(grpc_exec_ctx *exec_ctx,
+                                  grpc_lb_policy *policy,
+                                  const grpc_lb_policy_args *lb_policy_args);
+
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.c
index 67baa46de7..52c6e38c87 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -68,7 +53,7 @@ static void on_complete_for_send(grpc_exec_ctx *exec_ctx, void *arg,
   if (error == GRPC_ERROR_NONE) {
     calld->send_initial_metadata_succeeded = true;
   }
-  grpc_closure_run(exec_ctx, calld->original_on_complete_for_send,
+  GRPC_CLOSURE_RUN(exec_ctx, calld->original_on_complete_for_send,
                    GRPC_ERROR_REF(error));
 }
 
@@ -78,7 +63,7 @@ static void recv_initial_metadata_ready(grpc_exec_ctx *exec_ctx, void *arg,
   if (error == GRPC_ERROR_NONE) {
     calld->recv_initial_metadata_succeeded = true;
   }
-  grpc_closure_run(exec_ctx, calld->original_recv_initial_metadata_ready,
+  GRPC_CLOSURE_RUN(exec_ctx, calld->original_recv_initial_metadata_ready,
                    GRPC_ERROR_REF(error));
 }
 
@@ -119,7 +104,7 @@ static void start_transport_stream_op_batch(
   // Intercept send_initial_metadata.
   if (batch->send_initial_metadata) {
     calld->original_on_complete_for_send = batch->on_complete;
-    grpc_closure_init(&calld->on_complete_for_send, on_complete_for_send, calld,
+    GRPC_CLOSURE_INIT(&calld->on_complete_for_send, on_complete_for_send, calld,
                       grpc_schedule_on_exec_ctx);
     batch->on_complete = &calld->on_complete_for_send;
   }
@@ -127,7 +112,7 @@ static void start_transport_stream_op_batch(
   if (batch->recv_initial_metadata) {
     calld->original_recv_initial_metadata_ready =
         batch->payload->recv_initial_metadata.recv_initial_metadata_ready;
-    grpc_closure_init(&calld->recv_initial_metadata_ready,
+    GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
                       recv_initial_metadata_ready, calld,
                       grpc_schedule_on_exec_ctx);
     batch->payload->recv_initial_metadata.recv_initial_metadata_ready =
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
index 28b313d874..51e30b20b8 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
index b7c0e929b7..cccc3e871a 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -115,6 +100,7 @@
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/channel_stack.h"
 #include "src/core/lib/iomgr/combiner.h"
@@ -137,7 +123,7 @@
 #define GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS 120
 #define GRPC_GRPCLB_RECONNECT_JITTER 0.2
 
-grpc_tracer_flag grpc_lb_glb_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_lb_glb_trace = GRPC_TRACER_INITIALIZER(false, "glb");
 
 /* add lb_token of selected subchannel (address) to the call's initial
  * metadata */
@@ -198,7 +184,7 @@ static void wrapped_rr_closure(grpc_exec_ctx *exec_ctx, void *arg,
   wrapped_rr_closure_arg *wc_arg = arg;
 
   GPR_ASSERT(wc_arg->wrapped_closure != NULL);
-  grpc_closure_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error));
+  GRPC_CLOSURE_SCHED(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error));
 
   if (wc_arg->rr_policy != NULL) {
     /* if *target is NULL, no pick has been made by the RR policy (eg, all
@@ -270,7 +256,7 @@ static void add_pending_pick(pending_pick **root,
   pp->wrapped_on_complete_arg.lb_token_mdelem_storage =
       pick_args->lb_token_mdelem_storage;
   pp->wrapped_on_complete_arg.free_when_done = pp;
-  grpc_closure_init(&pp->wrapped_on_complete_arg.wrapper_closure,
+  GRPC_CLOSURE_INIT(&pp->wrapped_on_complete_arg.wrapper_closure,
                     wrapped_rr_closure, &pp->wrapped_on_complete_arg,
                     grpc_schedule_on_exec_ctx);
   *root = pp;
@@ -289,7 +275,7 @@ static void add_pending_ping(pending_ping **root, grpc_closure *notify) {
   pping->wrapped_notify_arg.wrapped_closure = notify;
   pping->wrapped_notify_arg.free_when_done = pping;
   pping->next = *root;
-  grpc_closure_init(&pping->wrapped_notify_arg.wrapper_closure,
+  GRPC_CLOSURE_INIT(&pping->wrapped_notify_arg.wrapper_closure,
                     wrapped_rr_closure, &pping->wrapped_notify_arg,
                     grpc_schedule_on_exec_ctx);
   *root = pping;
@@ -315,6 +301,9 @@ typedef struct glb_lb_policy {
   /** for communicating with the LB server */
   grpc_channel *lb_channel;
 
+  /** response generator to inject address updates into \a lb_channel */
+  grpc_fake_resolver_response_generator *response_generator;
+
   /** the RR policy to use of the backend servers returned by the LB server */
   grpc_lb_policy *rr_policy;
 
@@ -323,10 +312,18 @@ typedef struct glb_lb_policy {
   /** our connectivity state tracker */
   grpc_connectivity_state_tracker state_tracker;
 
+  /** connectivity state of the LB channel */
+  grpc_connectivity_state lb_channel_connectivity;
+
   /** stores the deserialized response from the LB. May be NULL until one such
    * response has arrived. */
   grpc_grpclb_serverlist *serverlist;
 
+  /** Index into serverlist for next pick.
+   * If the server at this index is a drop, we return a drop.
+   * Otherwise, we delegate to the RR policy. */
+  size_t serverlist_index;
+
   /** list of picks that are waiting on RR's policy connectivity */
   pending_pick *pending_picks;
 
@@ -335,10 +332,27 @@ typedef struct glb_lb_policy {
 
   bool shutting_down;
 
+  /** are we currently updating lb_call? */
+  bool updating_lb_call;
+
+  /** are we currently updating lb_channel? */
+  bool updating_lb_channel;
+
+  /** are we already watching the LB channel's connectivity? */
+  bool watching_lb_channel;
+
+  /** is \a lb_call_retry_timer active? */
+  bool retry_timer_active;
+
+  /** called upon changes to the LB channel's connectivity. */
+  grpc_closure lb_channel_on_connectivity_changed;
+
+  /** args from the latest update received while already updating, or NULL */
+  grpc_lb_policy_args *pending_update_args;
+
   /************************************************************/
   /*  client data associated with the LB server communication */
   /************************************************************/
-
   /* Finished sending initial request. */
   grpc_closure lb_on_sent_initial_request;
 
@@ -402,6 +416,9 @@ struct rr_connectivity_data {
 
 static bool is_server_valid(const grpc_grpclb_server *server, size_t idx,
                             bool log) {
+  if (server->drop_for_rate_limiting || server->drop_for_load_balancing) {
+    return false;
+  }
   const grpc_grpclb_ip_address *ip = &server->ip_address;
   if (server->port >> 16 != 0) {
     if (log) {
@@ -411,7 +428,6 @@ static bool is_server_valid(const grpc_grpclb_server *server, size_t idx,
     }
     return false;
   }
-
   if (ip->size != 4 && ip->size != 16) {
     if (log) {
       gpr_log(GPR_ERROR,
@@ -445,11 +461,12 @@ static const grpc_lb_user_data_vtable lb_token_vtable = {
 
 static void parse_server(const grpc_grpclb_server *server,
                          grpc_resolved_address *addr) {
+  memset(addr, 0, sizeof(*addr));
+  if (server->drop_for_rate_limiting || server->drop_for_load_balancing) return;
   const uint16_t netorder_port = htons((uint16_t)server->port);
   /* the addresses are given in binary format (a in(6)_addr struct) in
    * server->ip_address.bytes. */
   const grpc_grpclb_ip_address *ip = &server->ip_address;
-  memset(addr, 0, sizeof(*addr));
   if (ip->size == 4) {
     addr->len = sizeof(struct sockaddr_in);
     struct sockaddr_in *addr4 = (struct sockaddr_in *)&addr->addr;
@@ -525,10 +542,9 @@ static grpc_lb_addresses *process_serverlist_locked(
   return lb_addresses;
 }
 
-/* returns true if the new RR policy should replace the current one, if any */
-static bool update_lb_connectivity_status_locked(
+static void update_lb_connectivity_status_locked(
     grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
-    grpc_connectivity_state new_rr_state, grpc_error *new_rr_state_error) {
+    grpc_connectivity_state rr_state, grpc_error *rr_state_error) {
   const grpc_connectivity_state curr_glb_state =
       grpc_connectivity_state_check(&glb_policy->state_tracker);
 
@@ -562,40 +578,73 @@ static bool update_lb_connectivity_status_locked(
    *  (*) This function mustn't be called during shutting down. */
   GPR_ASSERT(curr_glb_state != GRPC_CHANNEL_SHUTDOWN);
 
-  switch (new_rr_state) {
+  switch (rr_state) {
     case GRPC_CHANNEL_TRANSIENT_FAILURE:
     case GRPC_CHANNEL_SHUTDOWN:
-      GPR_ASSERT(new_rr_state_error != GRPC_ERROR_NONE);
-      return false; /* don't replace the RR policy */
+      GPR_ASSERT(rr_state_error != GRPC_ERROR_NONE);
+      break;
     case GRPC_CHANNEL_INIT:
     case GRPC_CHANNEL_IDLE:
     case GRPC_CHANNEL_CONNECTING:
     case GRPC_CHANNEL_READY:
-      GPR_ASSERT(new_rr_state_error == GRPC_ERROR_NONE);
+      GPR_ASSERT(rr_state_error == GRPC_ERROR_NONE);
   }
 
   if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-    gpr_log(GPR_INFO,
-            "Setting grpclb's state to %s from new RR policy %p state.",
-            grpc_connectivity_state_name(new_rr_state),
-            (void *)glb_policy->rr_policy);
+    gpr_log(
+        GPR_INFO, "Setting grpclb's state to %s from new RR policy %p state.",
+        grpc_connectivity_state_name(rr_state), (void *)glb_policy->rr_policy);
   }
-  grpc_connectivity_state_set(exec_ctx, &glb_policy->state_tracker,
-                              new_rr_state, GRPC_ERROR_REF(new_rr_state_error),
+  grpc_connectivity_state_set(exec_ctx, &glb_policy->state_tracker, rr_state,
+                              GRPC_ERROR_REF(rr_state_error),
                               "update_lb_connectivity_status_locked");
-  return true;
 }
 
-/* perform a pick over \a rr_policy. Given that a pick can return immediately
- * (ignoring its completion callback) we need to perform the cleanups this
- * callback would be otherwise resposible for */
+/* Perform a pick over \a glb_policy->rr_policy. Given that a pick can return
+ * immediately (ignoring its completion callback), we need to perform the
+ * cleanups this callback would otherwise be resposible for.
+ * If \a force_async is true, then we will manually schedule the
+ * completion callback even if the pick is available immediately. */
 static bool pick_from_internal_rr_locked(
-    grpc_exec_ctx *exec_ctx, grpc_lb_policy *rr_policy,
-    const grpc_lb_policy_pick_args *pick_args,
+    grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
+    const grpc_lb_policy_pick_args *pick_args, bool force_async,
     grpc_connected_subchannel **target, wrapped_rr_closure_arg *wc_arg) {
-  GPR_ASSERT(rr_policy != NULL);
+  // Look at the index into the serverlist to see if we should drop this call.
+  grpc_grpclb_server *server =
+      glb_policy->serverlist->servers[glb_policy->serverlist_index++];
+  if (glb_policy->serverlist_index == glb_policy->serverlist->num_servers) {
+    glb_policy->serverlist_index = 0;  // Wrap-around.
+  }
+  if (server->drop_for_rate_limiting || server->drop_for_load_balancing) {
+    // Not using the RR policy, so unref it.
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_INFO, "Unreffing RR for drop (0x%" PRIxPTR ")",
+              (intptr_t)wc_arg->rr_policy);
+    }
+    GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
+    // Update client load reporting stats to indicate the number of
+    // dropped calls.  Note that we have to do this here instead of in
+    // the client_load_reporting filter, because we do not create a
+    // subchannel call (and therefore no client_load_reporting filter)
+    // for dropped calls.
+    grpc_grpclb_client_stats_add_call_started(wc_arg->client_stats);
+    grpc_grpclb_client_stats_add_call_finished(
+        server->drop_for_rate_limiting, server->drop_for_load_balancing,
+        false /* failed_to_send */, false /* known_received */,
+        wc_arg->client_stats);
+    grpc_grpclb_client_stats_unref(wc_arg->client_stats);
+    if (force_async) {
+      GPR_ASSERT(wc_arg->wrapped_closure != NULL);
+      GRPC_CLOSURE_SCHED(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+      gpr_free(wc_arg->free_when_done);
+      return false;
+    }
+    gpr_free(wc_arg->free_when_done);
+    return true;
+  }
+  // Pick via the RR policy.
   const bool pick_done = grpc_lb_policy_pick_locked(
-      exec_ctx, rr_policy, pick_args, target, wc_arg->context,
+      exec_ctx, wc_arg->rr_policy, pick_args, target, wc_arg->context,
       (void **)&wc_arg->lb_token, &wc_arg->wrapper_closure);
   if (pick_done) {
     /* synchronous grpc_lb_policy_pick call. Unref the RR policy. */
@@ -604,17 +653,20 @@ static bool pick_from_internal_rr_locked(
               (intptr_t)wc_arg->rr_policy);
     }
     GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
-
     /* add the load reporting initial metadata */
     initial_metadata_add_lb_token(exec_ctx, pick_args->initial_metadata,
                                   pick_args->lb_token_mdelem_storage,
                                   GRPC_MDELEM_REF(wc_arg->lb_token));
-
     // Pass on client stats via context. Passes ownership of the reference.
     GPR_ASSERT(wc_arg->client_stats != NULL);
     wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].value = wc_arg->client_stats;
     wc_arg->context[GRPC_GRPCLB_CLIENT_STATS].destroy = destroy_client_stats;
-
+    if (force_async) {
+      GPR_ASSERT(wc_arg->wrapped_closure != NULL);
+      GRPC_CLOSURE_SCHED(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+      gpr_free(wc_arg->free_when_done);
+      return false;
+    }
     gpr_free(wc_arg->free_when_done);
   }
   /* else, the pending pick will be registered and taken care of by the
@@ -624,45 +676,38 @@ static bool pick_from_internal_rr_locked(
   return pick_done;
 }
 
-static grpc_lb_policy *create_rr_locked(
-    grpc_exec_ctx *exec_ctx, const grpc_grpclb_serverlist *serverlist,
-    glb_lb_policy *glb_policy) {
-  GPR_ASSERT(serverlist != NULL && serverlist->num_servers > 0);
-
-  grpc_lb_policy_args args;
-  memset(&args, 0, sizeof(args));
-  args.client_channel_factory = glb_policy->cc_factory;
-  args.combiner = glb_policy->base.combiner;
+static grpc_lb_policy_args *lb_policy_args_create(grpc_exec_ctx *exec_ctx,
+                                                  glb_lb_policy *glb_policy) {
+  grpc_lb_policy_args *args = gpr_zalloc(sizeof(*args));
+  args->client_channel_factory = glb_policy->cc_factory;
+  args->combiner = glb_policy->base.combiner;
   grpc_lb_addresses *addresses =
-      process_serverlist_locked(exec_ctx, serverlist);
-
+      process_serverlist_locked(exec_ctx, glb_policy->serverlist);
   // Replace the LB addresses in the channel args that we pass down to
   // the subchannel.
   static const char *keys_to_remove[] = {GRPC_ARG_LB_ADDRESSES};
   const grpc_arg arg = grpc_lb_addresses_create_channel_arg(addresses);
-  args.args = grpc_channel_args_copy_and_add_and_remove(
+  args->args = grpc_channel_args_copy_and_add_and_remove(
       glb_policy->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &arg,
       1);
-
-  grpc_lb_policy *rr = grpc_lb_policy_create(exec_ctx, "round_robin", &args);
-  GPR_ASSERT(rr != NULL);
   grpc_lb_addresses_destroy(exec_ctx, addresses);
-  grpc_channel_args_destroy(exec_ctx, args.args);
-  return rr;
+  return args;
+}
+
+static void lb_policy_args_destroy(grpc_exec_ctx *exec_ctx,
+                                   grpc_lb_policy_args *args) {
+  grpc_channel_args_destroy(exec_ctx, args->args);
+  gpr_free(args);
 }
 
 static void glb_rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx,
                                                void *arg, grpc_error *error);
-/* glb_policy->rr_policy may be NULL (initial handover) */
-static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
-                               glb_lb_policy *glb_policy) {
-  GPR_ASSERT(glb_policy->serverlist != NULL &&
-             glb_policy->serverlist->num_servers > 0);
-
-  if (glb_policy->shutting_down) return;
+static void create_rr_locked(grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
+                             grpc_lb_policy_args *args) {
+  GPR_ASSERT(glb_policy->rr_policy == NULL);
 
   grpc_lb_policy *new_rr_policy =
-      create_rr_locked(exec_ctx, glb_policy->serverlist, glb_policy);
+      grpc_lb_policy_create(exec_ctx, "round_robin", args);
   if (new_rr_policy == NULL) {
     gpr_log(GPR_ERROR,
             "Failure creating a RoundRobin policy for serverlist update with "
@@ -673,41 +718,16 @@ static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
             (void *)glb_policy->rr_policy);
     return;
   }
-
-  grpc_error *new_rr_state_error = NULL;
-  const grpc_connectivity_state new_rr_state =
-      grpc_lb_policy_check_connectivity_locked(exec_ctx, new_rr_policy,
-                                               &new_rr_state_error);
-  /* Connectivity state is a function of the new RR policy just created */
-  const bool replace_old_rr = update_lb_connectivity_status_locked(
-      exec_ctx, glb_policy, new_rr_state, new_rr_state_error);
-
-  if (!replace_old_rr) {
-    /* dispose of the new RR policy that won't be used after all */
-    GRPC_LB_POLICY_UNREF(exec_ctx, new_rr_policy, "rr_handover_no_replace");
-    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-      gpr_log(GPR_INFO,
-              "Keeping old RR policy (%p) despite new serverlist: new RR "
-              "policy was in %s connectivity state.",
-              (void *)glb_policy->rr_policy,
-              grpc_connectivity_state_name(new_rr_state));
-    }
-    return;
-  }
-
-  if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-    gpr_log(GPR_INFO, "Created RR policy (%p) to replace old RR (%p)",
-            (void *)new_rr_policy, (void *)glb_policy->rr_policy);
-  }
-
-  if (glb_policy->rr_policy != NULL) {
-    /* if we are phasing out an existing RR instance, unref it. */
-    GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "rr_handover");
-  }
-
-  /* Finally update the RR policy to the newly created one */
   glb_policy->rr_policy = new_rr_policy;
 
+  grpc_error *rr_state_error = NULL;
+  const grpc_connectivity_state rr_state =
+      grpc_lb_policy_check_connectivity_locked(exec_ctx, glb_policy->rr_policy,
+                                               &rr_state_error);
+  /* Connectivity state is a function of the RR policy updated/created */
+  update_lb_connectivity_status_locked(exec_ctx, glb_policy, rr_state,
+                                       rr_state_error);
+
   /* Add the gRPC LB's interested_parties pollset_set to that of the newly
    * created RR policy. This will make the RR policy progress upon activity on
    * gRPC LB, which in turn is tied to the application's call */
@@ -719,14 +739,14 @@ static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
    * It'll be deallocated in glb_rr_connectivity_changed() */
   rr_connectivity_data *rr_connectivity =
       gpr_zalloc(sizeof(rr_connectivity_data));
-  grpc_closure_init(&rr_connectivity->on_change,
+  GRPC_CLOSURE_INIT(&rr_connectivity->on_change,
                     glb_rr_connectivity_changed_locked, rr_connectivity,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
   rr_connectivity->glb_policy = glb_policy;
-  rr_connectivity->state = new_rr_state;
+  rr_connectivity->state = rr_state;
 
   /* Subscribe to changes to the connectivity of the new RR */
-  GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "rr_connectivity_cb");
+  GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "rr_connectivity_sched");
   grpc_lb_policy_notify_on_state_change_locked(exec_ctx, glb_policy->rr_policy,
                                                &rr_connectivity->state,
                                                &rr_connectivity->on_change);
@@ -744,8 +764,8 @@ static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
       gpr_log(GPR_INFO, "Pending pick about to PICK from 0x%" PRIxPTR "",
               (intptr_t)glb_policy->rr_policy);
     }
-    pick_from_internal_rr_locked(exec_ctx, glb_policy->rr_policy,
-                                 &pp->pick_args, pp->target,
+    pick_from_internal_rr_locked(exec_ctx, glb_policy, &pp->pick_args,
+                                 true /* force_async */, pp->target,
                                  &pp->wrapped_on_complete_arg);
   }
 
@@ -763,6 +783,31 @@ static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
   }
 }
 
+/* glb_policy->rr_policy may be NULL (initial handover) */
+static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
+                               glb_lb_policy *glb_policy) {
+  GPR_ASSERT(glb_policy->serverlist != NULL &&
+             glb_policy->serverlist->num_servers > 0);
+
+  if (glb_policy->shutting_down) return;
+
+  grpc_lb_policy_args *args = lb_policy_args_create(exec_ctx, glb_policy);
+  if (glb_policy->rr_policy != NULL) {
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_DEBUG, "Updating Round Robin policy (%p)",
+              (void *)glb_policy->rr_policy);
+    }
+    grpc_lb_policy_update_locked(exec_ctx, glb_policy->rr_policy, args);
+  } else {
+    create_rr_locked(exec_ctx, glb_policy, args);
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_DEBUG, "Created new Round Robin policy (%p)",
+              (void *)glb_policy->rr_policy);
+    }
+  }
+  lb_policy_args_destroy(exec_ctx, args);
+}
+
 static void glb_rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx,
                                                void *arg, grpc_error *error) {
   rr_connectivity_data *rr_connectivity = arg;
@@ -808,18 +853,24 @@ static grpc_slice_hash_table_entry targets_info_entry_create(
   return entry;
 }
 
-/* Returns the target URI for the LB service whose addresses are in \a
- * addresses.  Using this URI, a bidirectional streaming channel will be created
- * for the reception of load balancing updates.
+static int balancer_name_cmp_fn(void *a, void *b) {
+  const char *a_str = a;
+  const char *b_str = b;
+  return strcmp(a_str, b_str);
+}
+
+/* Returns the channel args for the LB channel, used to create a bidirectional
+ * stream for the reception of load balancing updates.
  *
- * The output argument \a targets_info will be updated to contain a mapping of
- * "LB server address" to "balancer name", as reported by the naming system.
- * This mapping will be propagated via the channel arguments of the
- * aforementioned LB streaming channel, to be used by the security connector for
- * secure naming checks. The user is responsible for freeing \a targets_info. */
-static char *get_lb_uri_target_addresses(grpc_exec_ctx *exec_ctx,
-                                         const grpc_lb_addresses *addresses,
-                                         grpc_slice_hash_table **targets_info) {
+ * Inputs:
+ *   - \a addresses: corresponding to the balancers.
+ *   - \a response_generator: in order to propagate updates from the resolver
+ *   above the grpclb policy.
+ *   - \a args: other args inherited from the grpclb policy. */
+static grpc_channel_args *build_lb_channel_args(
+    grpc_exec_ctx *exec_ctx, const grpc_lb_addresses *addresses,
+    grpc_fake_resolver_response_generator *response_generator,
+    const grpc_channel_args *args) {
   size_t num_grpclb_addrs = 0;
   for (size_t i = 0; i < addresses->num_addresses; ++i) {
     if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
@@ -828,53 +879,54 @@ static char *get_lb_uri_target_addresses(grpc_exec_ctx *exec_ctx,
    * It's the resolver's responsibility to make sure this policy is only
    * instantiated and used in that case. Otherwise, something has gone wrong. */
   GPR_ASSERT(num_grpclb_addrs > 0);
-
+  grpc_lb_addresses *lb_addresses =
+      grpc_lb_addresses_create(num_grpclb_addrs, NULL);
   grpc_slice_hash_table_entry *targets_info_entries =
-      gpr_malloc(sizeof(*targets_info_entries) * num_grpclb_addrs);
-
-  /* construct a target ipvX://ip1:port1,ip2:port2,... from the addresses in \a
-   * addresses */
-  /* TODO(dgq): support mixed ip version */
-  char **addr_strs = gpr_malloc(sizeof(char *) * num_grpclb_addrs);
-  size_t addr_index = 0;
+      gpr_zalloc(sizeof(*targets_info_entries) * num_grpclb_addrs);
 
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
+  size_t lb_addresses_idx = 0;
+  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+    if (!addresses->addresses[i].is_balancer) continue;
     if (addresses->addresses[i].user_data != NULL) {
       gpr_log(GPR_ERROR,
               "This LB policy doesn't support user data. It will be ignored");
     }
-    if (addresses->addresses[i].is_balancer) {
-      char *addr_str;
-      GPR_ASSERT(grpc_sockaddr_to_string(
-                     &addr_str, &addresses->addresses[i].address, true) > 0);
-      targets_info_entries[addr_index] = targets_info_entry_create(
-          addr_str, addresses->addresses[i].balancer_name);
-      addr_strs[addr_index++] = addr_str;
-    }
+    char *addr_str;
+    GPR_ASSERT(grpc_sockaddr_to_string(
+                   &addr_str, &addresses->addresses[i].address, true) > 0);
+    targets_info_entries[lb_addresses_idx] = targets_info_entry_create(
+        addr_str, addresses->addresses[i].balancer_name);
+    gpr_free(addr_str);
+
+    grpc_lb_addresses_set_address(
+        lb_addresses, lb_addresses_idx++, addresses->addresses[i].address.addr,
+        addresses->addresses[i].address.len, false /* is balancer */,
+        addresses->addresses[i].balancer_name, NULL /* user data */);
   }
-  GPR_ASSERT(addr_index == num_grpclb_addrs);
-
-  size_t uri_path_len;
-  char *uri_path = gpr_strjoin_sep((const char **)addr_strs, num_grpclb_addrs,
-                                   ",", &uri_path_len);
-  for (size_t i = 0; i < num_grpclb_addrs; i++) gpr_free(addr_strs[i]);
-  gpr_free(addr_strs);
-
-  char *target_uri_str = NULL;
-  /* TODO(dgq): Don't assume all addresses will share the scheme of the first
-   * one */
-  gpr_asprintf(&target_uri_str, "%s:%s",
-               grpc_sockaddr_get_uri_scheme(&addresses->addresses[0].address),
-               uri_path);
-  gpr_free(uri_path);
-
-  *targets_info = grpc_slice_hash_table_create(
-      num_grpclb_addrs, targets_info_entries, destroy_balancer_name);
+  GPR_ASSERT(num_grpclb_addrs == lb_addresses_idx);
+  grpc_slice_hash_table *targets_info =
+      grpc_slice_hash_table_create(num_grpclb_addrs, targets_info_entries,
+                                   destroy_balancer_name, balancer_name_cmp_fn);
   gpr_free(targets_info_entries);
 
-  return target_uri_str;
+  grpc_channel_args *lb_channel_args =
+      grpc_lb_policy_grpclb_build_lb_channel_args(exec_ctx, targets_info,
+                                                  response_generator, args);
+
+  grpc_arg lb_channel_addresses_arg =
+      grpc_lb_addresses_create_channel_arg(lb_addresses);
+
+  grpc_channel_args *result = grpc_channel_args_copy_and_add(
+      lb_channel_args, &lb_channel_addresses_arg, 1);
+  grpc_slice_hash_table_unref(exec_ctx, targets_info);
+  grpc_channel_args_destroy(exec_ctx, lb_channel_args);
+  grpc_lb_addresses_destroy(exec_ctx, lb_addresses);
+  return result;
 }
 
+static void glb_lb_channel_on_connectivity_changed_cb(grpc_exec_ctx *exec_ctx,
+                                                      void *arg,
+                                                      grpc_error *error);
 static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
                                   grpc_lb_policy_factory *factory,
                                   grpc_lb_policy_args *args) {
@@ -922,32 +974,37 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
 
   // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
   // since we use this to trigger the client_load_reporting filter.
-  grpc_arg new_arg;
-  new_arg.key = GRPC_ARG_LB_POLICY_NAME;
-  new_arg.type = GRPC_ARG_STRING;
-  new_arg.value.string = "grpclb";
+  grpc_arg new_arg =
+      grpc_channel_arg_string_create(GRPC_ARG_LB_POLICY_NAME, "grpclb");
   static const char *args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME};
   glb_policy->args = grpc_channel_args_copy_and_add_and_remove(
       args->args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
 
-  grpc_slice_hash_table *targets_info = NULL;
   /* Create a client channel over them to communicate with a LB service */
-  char *lb_service_target_addresses =
-      get_lb_uri_target_addresses(exec_ctx, addresses, &targets_info);
-  grpc_channel_args *lb_channel_args =
-      get_lb_channel_args(exec_ctx, targets_info, args->args);
+  glb_policy->response_generator =
+      grpc_fake_resolver_response_generator_create();
+  grpc_channel_args *lb_channel_args = build_lb_channel_args(
+      exec_ctx, addresses, glb_policy->response_generator, args->args);
+  char *uri_str;
+  gpr_asprintf(&uri_str, "fake:///%s", glb_policy->server_name);
   glb_policy->lb_channel = grpc_lb_policy_grpclb_create_lb_channel(
-      exec_ctx, lb_service_target_addresses, args->client_channel_factory,
-      lb_channel_args);
-  grpc_slice_hash_table_unref(exec_ctx, targets_info);
+      exec_ctx, uri_str, args->client_channel_factory, lb_channel_args);
+
+  /* Propagate initial resolution */
+  grpc_fake_resolver_response_generator_set_response(
+      exec_ctx, glb_policy->response_generator, lb_channel_args);
   grpc_channel_args_destroy(exec_ctx, lb_channel_args);
-  gpr_free(lb_service_target_addresses);
+  gpr_free(uri_str);
   if (glb_policy->lb_channel == NULL) {
     gpr_free((void *)glb_policy->server_name);
     grpc_channel_args_destroy(exec_ctx, glb_policy->args);
     gpr_free(glb_policy);
     return NULL;
   }
+
+  GRPC_CLOSURE_INIT(&glb_policy->lb_channel_on_connectivity_changed,
+                    glb_lb_channel_on_connectivity_changed_cb, glb_policy,
+                    grpc_combiner_scheduler(args->combiner));
   grpc_lb_policy_init(&glb_policy->base, &glb_lb_policy_vtable, args->combiner);
   grpc_connectivity_state_init(&glb_policy->state_tracker, GRPC_CHANNEL_IDLE,
                                "grpclb");
@@ -963,12 +1020,15 @@ static void glb_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   if (glb_policy->client_stats != NULL) {
     grpc_grpclb_client_stats_unref(glb_policy->client_stats);
   }
-  grpc_channel_destroy(glb_policy->lb_channel);
-  glb_policy->lb_channel = NULL;
   grpc_connectivity_state_destroy(exec_ctx, &glb_policy->state_tracker);
   if (glb_policy->serverlist != NULL) {
     grpc_grpclb_destroy_serverlist(glb_policy->serverlist);
   }
+  grpc_fake_resolver_response_generator_unref(glb_policy->response_generator);
+  if (glb_policy->pending_update_args != NULL) {
+    grpc_channel_args_destroy(exec_ctx, glb_policy->pending_update_args->args);
+    gpr_free(glb_policy->pending_update_args);
+  }
   gpr_free(glb_policy);
 }
 
@@ -976,16 +1036,6 @@ static void glb_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   glb_lb_policy *glb_policy = (glb_lb_policy *)pol;
   glb_policy->shutting_down = true;
 
-  pending_pick *pp = glb_policy->pending_picks;
-  glb_policy->pending_picks = NULL;
-  pending_ping *pping = glb_policy->pending_pings;
-  glb_policy->pending_pings = NULL;
-  if (glb_policy->rr_policy) {
-    GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "glb_shutdown");
-  }
-  grpc_connectivity_state_set(
-      exec_ctx, &glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN,
-      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown"), "glb_shutdown");
   /* We need a copy of the lb_call pointer because we can't cancell the call
    * while holding glb_policy->mu: lb_on_server_status_received, invoked due to
    * the cancel, needs to acquire that same lock */
@@ -999,17 +1049,41 @@ static void glb_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
     grpc_call_cancel(lb_call, NULL);
     /* lb_on_server_status_received will pick up the cancel and clean up */
   }
+  if (glb_policy->retry_timer_active) {
+    grpc_timer_cancel(exec_ctx, &glb_policy->lb_call_retry_timer);
+    glb_policy->retry_timer_active = false;
+  }
+
+  pending_pick *pp = glb_policy->pending_picks;
+  glb_policy->pending_picks = NULL;
+  pending_ping *pping = glb_policy->pending_pings;
+  glb_policy->pending_pings = NULL;
+  if (glb_policy->rr_policy) {
+    GRPC_LB_POLICY_UNREF(exec_ctx, glb_policy->rr_policy, "glb_shutdown");
+  }
+  // We destroy the LB channel here because
+  // glb_lb_channel_on_connectivity_changed_cb needs a valid glb_policy
+  // instance.  Destroying the lb channel in glb_destroy would likely result in
+  // a callback invocation without a valid glb_policy arg.
+  if (glb_policy->lb_channel != NULL) {
+    grpc_channel_destroy(glb_policy->lb_channel);
+    glb_policy->lb_channel = NULL;
+  }
+  grpc_connectivity_state_set(
+      exec_ctx, &glb_policy->state_tracker, GRPC_CHANNEL_SHUTDOWN,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown"), "glb_shutdown");
+
   while (pp != NULL) {
     pending_pick *next = pp->next;
     *pp->target = NULL;
-    grpc_closure_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
+    GRPC_CLOSURE_SCHED(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
                        GRPC_ERROR_NONE);
     pp = next;
   }
 
   while (pping != NULL) {
     pending_ping *next = pping->next;
-    grpc_closure_sched(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure,
+    GRPC_CLOSURE_SCHED(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure,
                        GRPC_ERROR_NONE);
     pping = next;
   }
@@ -1025,7 +1099,7 @@ static void glb_cancel_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_closure_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
+      GRPC_CLOSURE_SCHED(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick Cancelled", &error, 1));
     } else {
@@ -1049,7 +1123,7 @@ static void glb_cancel_picks_locked(grpc_exec_ctx *exec_ctx,
     pending_pick *next = pp->next;
     if ((pp->pick_args.initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
-      grpc_closure_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
+      GRPC_CLOSURE_SCHED(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick Cancelled", &error, 1));
     } else {
@@ -1084,7 +1158,7 @@ static int glb_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                            grpc_closure *on_complete) {
   if (pick_args->lb_token_mdelem_storage == NULL) {
     *target = NULL;
-    grpc_closure_sched(exec_ctx, on_complete,
+    GRPC_CLOSURE_SCHED(exec_ctx, on_complete,
                        GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                            "No mdelem storage for the LB token. Load reporting "
                            "won't work without it. Failing"));
@@ -1103,7 +1177,7 @@ static int glb_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
     wrapped_rr_closure_arg *wc_arg = gpr_zalloc(sizeof(wrapped_rr_closure_arg));
 
-    grpc_closure_init(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg,
+    GRPC_CLOSURE_INIT(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg,
                       grpc_schedule_on_exec_ctx);
     wc_arg->rr_policy = glb_policy->rr_policy;
     wc_arg->target = target;
@@ -1115,8 +1189,9 @@ static int glb_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     wc_arg->lb_token_mdelem_storage = pick_args->lb_token_mdelem_storage;
     wc_arg->initial_metadata = pick_args->initial_metadata;
     wc_arg->free_when_done = wc_arg;
-    pick_done = pick_from_internal_rr_locked(exec_ctx, glb_policy->rr_policy,
-                                             pick_args, target, wc_arg);
+    pick_done =
+        pick_from_internal_rr_locked(exec_ctx, glb_policy, pick_args,
+                                     false /* force_async */, target, wc_arg);
   } else {
     if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
       gpr_log(GPR_DEBUG,
@@ -1173,9 +1248,9 @@ static void schedule_next_client_load_report(grpc_exec_ctx *exec_ctx,
   const gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   const gpr_timespec next_client_load_report_time =
       gpr_time_add(now, glb_policy->client_stats_report_interval);
-  grpc_closure_init(&glb_policy->client_load_report_closure,
+  GRPC_CLOSURE_INIT(&glb_policy->client_load_report_closure,
                     send_client_load_report_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
   grpc_timer_init(exec_ctx, &glb_policy->client_load_report_timer,
                   next_client_load_report_time,
                   &glb_policy->client_load_report_closure, now);
@@ -1201,9 +1276,9 @@ static void do_send_client_load_report_locked(grpc_exec_ctx *exec_ctx,
   memset(&op, 0, sizeof(op));
   op.op = GRPC_OP_SEND_MESSAGE;
   op.data.send_message.send_message = glb_policy->client_load_report_payload;
-  grpc_closure_init(&glb_policy->client_load_report_closure,
+  GRPC_CLOSURE_INIT(&glb_policy->client_load_report_closure,
                     client_load_report_done_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
   grpc_call_error call_error = grpc_call_start_batch_and_execute(
       exec_ctx, glb_policy->lb_call, &op, 1,
       &glb_policy->client_load_report_closure);
@@ -1271,6 +1346,7 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
                                 glb_lb_policy *glb_policy) {
   GPR_ASSERT(glb_policy->server_name != NULL);
   GPR_ASSERT(glb_policy->server_name[0] != '\0');
+  GPR_ASSERT(glb_policy->lb_call == NULL);
   GPR_ASSERT(!glb_policy->shutting_down);
 
   /* Note the following LB call progresses every time there's activity in \a
@@ -1306,15 +1382,15 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
   grpc_slice_unref_internal(exec_ctx, request_payload_slice);
   grpc_grpclb_request_destroy(request);
 
-  grpc_closure_init(&glb_policy->lb_on_sent_initial_request,
+  GRPC_CLOSURE_INIT(&glb_policy->lb_on_sent_initial_request,
                     lb_on_sent_initial_request_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
-  grpc_closure_init(&glb_policy->lb_on_server_status_received,
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
+  GRPC_CLOSURE_INIT(&glb_policy->lb_on_server_status_received,
                     lb_on_server_status_received_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
-  grpc_closure_init(&glb_policy->lb_on_response_received,
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
+  GRPC_CLOSURE_INIT(&glb_policy->lb_on_response_received,
                     lb_on_response_received_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner, false));
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
 
   gpr_backoff_init(&glb_policy->lb_call_backoff_state,
                    GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS,
@@ -1356,8 +1432,10 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   lb_call_init_locked(exec_ctx, glb_policy);
 
   if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-    gpr_log(GPR_INFO, "Query for backends (grpclb: %p, lb_call: %p)",
-            (void *)glb_policy, (void *)glb_policy->lb_call);
+    gpr_log(GPR_INFO,
+            "Query for backends (grpclb: %p, lb_channel: %p, lb_call: %p)",
+            (void *)glb_policy, (void *)glb_policy->lb_channel,
+            (void *)glb_policy->lb_call);
   }
   GPR_ASSERT(glb_policy->lb_call != NULL);
 
@@ -1517,7 +1595,7 @@ static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
              * serverlist instance will be destroyed either upon the next
              * update or in glb_destroy() */
             glb_policy->serverlist = serverlist;
-
+            glb_policy->serverlist_index = 0;
             rr_handover_locked(exec_ctx, glb_policy);
           }
         } else {
@@ -1561,8 +1639,8 @@ static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
 static void lb_call_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                           grpc_error *error) {
   glb_lb_policy *glb_policy = arg;
-
-  if (!glb_policy->shutting_down) {
+  glb_policy->retry_timer_active = false;
+  if (!glb_policy->shutting_down && error == GRPC_ERROR_NONE) {
     if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
       gpr_log(GPR_INFO, "Restaring call to LB server (grpclb %p)",
               (void *)glb_policy);
@@ -1570,31 +1648,32 @@ static void lb_call_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
     GPR_ASSERT(glb_policy->lb_call == NULL);
     query_for_backends_locked(exec_ctx, glb_policy);
   }
-  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
-                            "grpclb_on_retry_timer");
+  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, "grpclb_retry_timer");
 }
 
 static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
                                                 void *arg, grpc_error *error) {
   glb_lb_policy *glb_policy = arg;
-
   GPR_ASSERT(glb_policy->lb_call != NULL);
-
   if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
     char *status_details =
         grpc_slice_to_c_string(glb_policy->lb_call_status_details);
-    gpr_log(GPR_DEBUG,
+    gpr_log(GPR_INFO,
             "Status from LB server received. Status = %d, Details = '%s', "
-            "(call: %p)",
+            "(call: %p), error %p",
             glb_policy->lb_call_status, status_details,
-            (void *)glb_policy->lb_call);
+            (void *)glb_policy->lb_call, (void *)error);
     gpr_free(status_details);
   }
-
   /* We need to perform cleanups no matter what. */
   lb_call_destroy_locked(exec_ctx, glb_policy);
-
-  if (!glb_policy->shutting_down) {
+  if (glb_policy->started_picking && glb_policy->updating_lb_call) {
+    if (glb_policy->retry_timer_active) {
+      grpc_timer_cancel(exec_ctx, &glb_policy->lb_call_retry_timer);
+    }
+    if (!glb_policy->shutting_down) start_picking_locked(exec_ctx, glb_policy);
+    glb_policy->updating_lb_call = false;
+  } else if (!glb_policy->shutting_down) {
     /* if we aren't shutting down, restart the LB client call after some time */
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_timespec next_try =
@@ -1604,16 +1683,18 @@ static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
               (void *)glb_policy);
       gpr_timespec timeout = gpr_time_sub(next_try, now);
       if (gpr_time_cmp(timeout, gpr_time_0(timeout.clock_type)) > 0) {
-        gpr_log(GPR_DEBUG, "... retrying in %" PRId64 ".%09d seconds.",
+        gpr_log(GPR_DEBUG,
+                "... retry_timer_active in %" PRId64 ".%09d seconds.",
                 timeout.tv_sec, timeout.tv_nsec);
       } else {
-        gpr_log(GPR_DEBUG, "... retrying immediately.");
+        gpr_log(GPR_DEBUG, "... retry_timer_active immediately.");
       }
     }
     GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer");
-    grpc_closure_init(
-        &glb_policy->lb_on_call_retry, lb_call_on_retry_timer_locked,
-        glb_policy, grpc_combiner_scheduler(glb_policy->base.combiner, false));
+    GRPC_CLOSURE_INIT(&glb_policy->lb_on_call_retry,
+                      lb_call_on_retry_timer_locked, glb_policy,
+                      grpc_combiner_scheduler(glb_policy->base.combiner));
+    glb_policy->retry_timer_active = true;
     grpc_timer_init(exec_ctx, &glb_policy->lb_call_retry_timer, next_try,
                     &glb_policy->lb_on_call_retry, now);
   }
@@ -1621,6 +1702,138 @@ static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
                             "lb_on_server_status_received");
 }
 
+static void glb_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                              const grpc_lb_policy_args *args) {
+  glb_lb_policy *glb_policy = (glb_lb_policy *)policy;
+
+  if (glb_policy->updating_lb_channel) {
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_INFO,
+              "Update already in progress for grpclb %p. Deferring update.",
+              (void *)glb_policy);
+    }
+    if (glb_policy->pending_update_args != NULL) {
+      grpc_channel_args_destroy(exec_ctx,
+                                glb_policy->pending_update_args->args);
+      gpr_free(glb_policy->pending_update_args);
+    }
+    glb_policy->pending_update_args =
+        gpr_zalloc(sizeof(*glb_policy->pending_update_args));
+    glb_policy->pending_update_args->client_channel_factory =
+        args->client_channel_factory;
+    glb_policy->pending_update_args->args = grpc_channel_args_copy(args->args);
+    glb_policy->pending_update_args->combiner = args->combiner;
+    return;
+  }
+
+  glb_policy->updating_lb_channel = true;
+  // Propagate update to lb_channel (pick first).
+  const grpc_arg *arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+  if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
+    if (glb_policy->lb_channel == NULL) {
+      // If we don't have a current channel to the LB, go into TRANSIENT
+      // FAILURE.
+      grpc_connectivity_state_set(
+          exec_ctx, &glb_policy->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing update in args"),
+          "glb_update_missing");
+    } else {
+      // otherwise, keep using the current LB channel (ignore this update).
+      gpr_log(GPR_ERROR,
+              "No valid LB addresses channel arg for grpclb %p update, "
+              "ignoring.",
+              (void *)glb_policy);
+    }
+  }
+  const grpc_lb_addresses *addresses = arg->value.pointer.p;
+  GPR_ASSERT(glb_policy->lb_channel != NULL);
+  grpc_channel_args *lb_channel_args = build_lb_channel_args(
+      exec_ctx, addresses, glb_policy->response_generator, args->args);
+  /* Propagate updates to the LB channel through the fake resolver */
+  grpc_fake_resolver_response_generator_set_response(
+      exec_ctx, glb_policy->response_generator, lb_channel_args);
+  grpc_channel_args_destroy(exec_ctx, lb_channel_args);
+
+  if (!glb_policy->watching_lb_channel) {
+    // Watch the LB channel connectivity for connection.
+    glb_policy->lb_channel_connectivity = GRPC_CHANNEL_INIT;
+    grpc_channel_element *client_channel_elem = grpc_channel_stack_last_element(
+        grpc_channel_get_channel_stack(glb_policy->lb_channel));
+    GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter);
+    glb_policy->watching_lb_channel = true;
+    GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "watch_lb_channel_connectivity");
+    grpc_client_channel_watch_connectivity_state(
+        exec_ctx, client_channel_elem,
+        grpc_polling_entity_create_from_pollset_set(
+            glb_policy->base.interested_parties),
+        &glb_policy->lb_channel_connectivity,
+        &glb_policy->lb_channel_on_connectivity_changed, NULL);
+  }
+}
+
+// Invoked as part of the update process. It continues watching the LB channel
+// until it shuts down or becomes READY. It's invoked even if the LB channel
+// stayed READY throughout the update (for example if the update is identical).
+static void glb_lb_channel_on_connectivity_changed_cb(grpc_exec_ctx *exec_ctx,
+                                                      void *arg,
+                                                      grpc_error *error) {
+  glb_lb_policy *glb_policy = arg;
+  if (glb_policy->shutting_down) goto done;
+  // Re-initialize the lb_call. This should also take care of updating the
+  // embedded RR policy. Note that the current RR policy, if any, will stay in
+  // effect until an update from the new lb_call is received.
+  switch (glb_policy->lb_channel_connectivity) {
+    case GRPC_CHANNEL_INIT:
+    case GRPC_CHANNEL_CONNECTING:
+    case GRPC_CHANNEL_TRANSIENT_FAILURE: {
+      /* resub. */
+      grpc_channel_element *client_channel_elem =
+          grpc_channel_stack_last_element(
+              grpc_channel_get_channel_stack(glb_policy->lb_channel));
+      GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter);
+      grpc_client_channel_watch_connectivity_state(
+          exec_ctx, client_channel_elem,
+          grpc_polling_entity_create_from_pollset_set(
+              glb_policy->base.interested_parties),
+          &glb_policy->lb_channel_connectivity,
+          &glb_policy->lb_channel_on_connectivity_changed, NULL);
+      break;
+    }
+    case GRPC_CHANNEL_IDLE:
+      // lb channel inactive (probably shutdown prior to update). Restart lb
+      // call to kick the lb channel into gear.
+      GPR_ASSERT(glb_policy->lb_call == NULL);
+    /* fallthrough */
+    case GRPC_CHANNEL_READY:
+      if (glb_policy->lb_call != NULL) {
+        glb_policy->updating_lb_channel = false;
+        glb_policy->updating_lb_call = true;
+        grpc_call_cancel(glb_policy->lb_call, NULL);
+        // lb_on_server_status_received will pick up the cancel and reinit
+        // lb_call.
+        if (glb_policy->pending_update_args != NULL) {
+          const grpc_lb_policy_args *args = glb_policy->pending_update_args;
+          glb_policy->pending_update_args = NULL;
+          glb_update_locked(exec_ctx, &glb_policy->base, args);
+        }
+      } else if (glb_policy->started_picking && !glb_policy->shutting_down) {
+        if (glb_policy->retry_timer_active) {
+          grpc_timer_cancel(exec_ctx, &glb_policy->lb_call_retry_timer);
+          glb_policy->retry_timer_active = false;
+        }
+        start_picking_locked(exec_ctx, glb_policy);
+      }
+    /* fallthrough */
+    case GRPC_CHANNEL_SHUTDOWN:
+    done:
+      glb_policy->watching_lb_channel = false;
+      GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
+                                "watch_lb_channel_connectivity_cb_shutdown");
+      break;
+  }
+}
+
 /* Code wiring the policy with the rest of the core */
 static const grpc_lb_policy_vtable glb_lb_policy_vtable = {
     glb_destroy,
@@ -1631,7 +1844,8 @@ static const grpc_lb_policy_vtable glb_lb_policy_vtable = {
     glb_ping_one_locked,
     glb_exit_idle_locked,
     glb_check_connectivity_locked,
-    glb_notify_on_state_change_locked};
+    glb_notify_on_state_change_locked,
+    glb_update_locked};
 
 static void glb_factory_ref(grpc_lb_policy_factory *factory) {}
 
@@ -1665,7 +1879,10 @@ static bool maybe_add_client_load_reporting_filter(
 
 void grpc_lb_policy_grpclb_init() {
   grpc_register_lb_policy(grpc_glb_lb_factory_create());
-  grpc_register_tracer("glb", &grpc_lb_glb_trace);
+  grpc_register_tracer(&grpc_lb_glb_trace);
+#ifndef NDEBUG
+  grpc_register_tracer(&grpc_trace_lb_policy_refcount);
+#endif
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
                                    GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
                                    maybe_add_client_load_reporting_filter,
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
index b069fae2f8..63ad66c5e9 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.c
index d6201f2387..f2967182e2 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -50,28 +35,37 @@ grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
   return lb_channel;
 }
 
-grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
-                                       grpc_slice_hash_table *targets_info,
-                                       const grpc_channel_args *args) {
-  /* We strip out the channel arg for the LB policy name, since we want
-   * to use the default (pick_first) in this case.
+grpc_channel_args *grpc_lb_policy_grpclb_build_lb_channel_args(
+    grpc_exec_ctx *exec_ctx, grpc_slice_hash_table *targets_info,
+    grpc_fake_resolver_response_generator *response_generator,
+    const grpc_channel_args *args) {
+  const grpc_arg to_add[] = {
+      grpc_fake_resolver_response_generator_arg(response_generator)};
+  /* We remove:
    *
-   * We also strip out the channel arg for the resolved addresses, since
-   * that will be generated by the name resolver used in the LB channel.
-   * Note that the LB channel will use the sockaddr resolver, so this
-   * won't actually generate a query to DNS (or some other name service).
-   * However, the addresses returned by the sockaddr resolver will have
-   * is_balancer=false, whereas our own addresses have is_balancer=true.
-   * We need the LB channel to return addresses with is_balancer=false
-   * so that it does not wind up recursively using the grpclb LB policy,
-   * as per the special case logic in client_channel.c.
+   * - The channel arg for the LB policy name, since we want to use the default
+   *   (pick_first) in this case.
    *
-   * Lastly, we also strip out the channel arg for the server URI,
-   * since that will be different for the LB channel than for the parent
-   * channel (the client channel factory will re-add this arg with
-   * the right value). */
+   * - The channel arg for the resolved addresses, since that will be generated
+   *   by the name resolver used in the LB channel.  Note that the LB channel
+   *   will use the fake resolver, so this won't actually generate a query
+   *   to DNS (or some other name service).  However, the addresses returned by
+   *   the fake resolver will have is_balancer=false, whereas our own
+   *   addresses have is_balancer=true.  We need the LB channel to return
+   *   addresses with is_balancer=false so that it does not wind up recursively
+   *   using the grpclb LB policy, as per the special case logic in
+   *   client_channel.c.
+   *
+   * - The channel arg for the server URI, since that will be different for the
+   *   LB channel than for the parent channel (the client channel factory will
+   *   re-add this arg with the right value).
+   *
+   * - The fake resolver generator, because we are replacing it with the one
+   *   from the grpclb policy, used to propagate updates to the LB channel. */
   static const char *keys_to_remove[] = {
-      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
-  return grpc_channel_args_copy_and_remove(args, keys_to_remove,
-                                           GPR_ARRAY_SIZE(keys_to_remove));
+      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI,
+      GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR};
+  return grpc_channel_args_copy_and_add_and_remove(
+      args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), to_add,
+      GPR_ARRAY_SIZE(to_add));
 }
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
index 9730c971d9..6120bf53f7 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -35,6 +20,7 @@
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H
 
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/lib/slice/slice_hash_table.h"
 
 /** Create the channel used for communicating with an LB service.
@@ -49,9 +35,10 @@ grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
     grpc_client_channel_factory *client_channel_factory,
     grpc_channel_args *args);
 
-grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
-                                       grpc_slice_hash_table *targets_info,
-                                       const grpc_channel_args *args);
+grpc_channel_args *grpc_lb_policy_grpclb_build_lb_channel_args(
+    grpc_exec_ctx *exec_ctx, grpc_slice_hash_table *targets_info,
+    grpc_fake_resolver_response_generator *response_generator,
+    const grpc_channel_args *args);
 
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H \
           */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.c
index a145cba63c..2681b2a079 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -76,32 +61,39 @@ grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
   return lb_channel;
 }
 
-grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
-                                       grpc_slice_hash_table *targets_info,
-                                       const grpc_channel_args *args) {
-  const grpc_arg targets_info_arg =
-      grpc_lb_targets_info_create_channel_arg(targets_info);
-  /* We strip out the channel arg for the LB policy name, since we want
-   * to use the default (pick_first) in this case.
+grpc_channel_args *grpc_lb_policy_grpclb_build_lb_channel_args(
+    grpc_exec_ctx *exec_ctx, grpc_slice_hash_table *targets_info,
+    grpc_fake_resolver_response_generator *response_generator,
+    const grpc_channel_args *args) {
+  const grpc_arg to_add[] = {
+      grpc_lb_targets_info_create_channel_arg(targets_info),
+      grpc_fake_resolver_response_generator_arg(response_generator)};
+  /* We remove:
    *
-   * We also strip out the channel arg for the resolved addresses, since
-   * that will be generated by the name resolver used in the LB channel.
-   * Note that the LB channel will use the sockaddr resolver, so this
-   * won't actually generate a query to DNS (or some other name service).
-   * However, the addresses returned by the sockaddr resolver will have
-   * is_balancer=false, whereas our own addresses have is_balancer=true.
-   * We need the LB channel to return addresses with is_balancer=false
-   * so that it does not wind up recursively using the grpclb LB policy,
-   * as per the special case logic in client_channel.c.
+   * - The channel arg for the LB policy name, since we want to use the default
+   *   (pick_first) in this case.
    *
-   * Lastly, we also strip out the channel arg for the server URI,
-   * since that will be different for the LB channel than for the parent
-   * channel (the client channel factory will re-add this arg with
-   * the right value). */
+   * - The channel arg for the resolved addresses, since that will be generated
+   *   by the name resolver used in the LB channel.  Note that the LB channel
+   *   will use the fake resolver, so this won't actually generate a query
+   *   to DNS (or some other name service).  However, the addresses returned by
+   *   the fake resolver will have is_balancer=false, whereas our own
+   *   addresses have is_balancer=true.  We need the LB channel to return
+   *   addresses with is_balancer=false so that it does not wind up recursively
+   *   using the grpclb LB policy, as per the special case logic in
+   *   client_channel.c.
+   *
+   * - The channel arg for the server URI, since that will be different for the
+   *   LB channel than for the parent channel (the client channel factory will
+   *   re-add this arg with the right value).
+   *
+   * - The fake resolver generator, because we are replacing it with the one
+   *   from the grpclb policy, used to propagate updates to the LB channel. */
   static const char *keys_to_remove[] = {
-      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
+      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI,
+      GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR};
   /* Add the targets info table to be used for secure naming */
   return grpc_channel_args_copy_and_add_and_remove(
-      args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &targets_info_arg,
-      1);
+      args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), to_add,
+      GPR_ARRAY_SIZE(to_add));
 }
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.c
index 444c03b9aa..c762443b7c 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
index 0af4a919f8..4bb47d5c5c 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.c
index 81b6932fae..bec7c97a78 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -37,44 +22,39 @@
 
 #include <grpc/support/alloc.h>
 
+/* invoked once for every Server in ServerList */
+static bool count_serverlist(pb_istream_t *stream, const pb_field_t *field,
+                             void **arg) {
+  grpc_grpclb_serverlist *sl = *arg;
+  grpc_grpclb_server server;
+  if (!pb_decode(stream, grpc_lb_v1_Server_fields, &server)) {
+    gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(stream));
+    return false;
+  }
+  ++sl->num_servers;
+  return true;
+}
+
 typedef struct decode_serverlist_arg {
-  /* The first pass counts the number of servers in the server list. The second
-   * one allocates and decodes. */
-  bool first_pass;
   /* The decoding callback is invoked once per server in serverlist. Remember
    * which index of the serverlist are we currently decoding */
   size_t decoding_idx;
-  /* Populated after the first pass. Number of server in the input serverlist */
-  size_t num_servers;
   /* The decoded serverlist */
-  grpc_grpclb_server **servers;
+  grpc_grpclb_serverlist *serverlist;
 } decode_serverlist_arg;
 
 /* invoked once for every Server in ServerList */
 static bool decode_serverlist(pb_istream_t *stream, const pb_field_t *field,
                               void **arg) {
   decode_serverlist_arg *dec_arg = *arg;
-  if (dec_arg->first_pass) { /* count how many server do we have */
-    grpc_grpclb_server server;
-    if (!pb_decode(stream, grpc_lb_v1_Server_fields, &server)) {
-      gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(stream));
-      return false;
-    }
-    dec_arg->num_servers++;
-  } else { /* second pass. Actually decode. */
-    grpc_grpclb_server *server = gpr_zalloc(sizeof(grpc_grpclb_server));
-    GPR_ASSERT(dec_arg->num_servers > 0);
-    if (dec_arg->decoding_idx == 0) { /* first iteration of second pass */
-      dec_arg->servers =
-          gpr_malloc(sizeof(grpc_grpclb_server *) * dec_arg->num_servers);
-    }
-    if (!pb_decode(stream, grpc_lb_v1_Server_fields, server)) {
-      gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(stream));
-      return false;
-    }
-    dec_arg->servers[dec_arg->decoding_idx++] = server;
+  GPR_ASSERT(dec_arg->serverlist->num_servers >= dec_arg->decoding_idx);
+  grpc_grpclb_server *server = gpr_zalloc(sizeof(grpc_grpclb_server));
+  if (!pb_decode(stream, grpc_lb_v1_Server_fields, server)) {
+    gpr_free(server);
+    gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(stream));
+    return false;
   }
-
+  dec_arg->serverlist->servers[dec_arg->decoding_idx++] = server;
   return true;
 }
 
@@ -165,36 +145,38 @@ grpc_grpclb_initial_response *grpc_grpclb_initial_response_parse(
 
 grpc_grpclb_serverlist *grpc_grpclb_response_parse_serverlist(
     grpc_slice encoded_grpc_grpclb_response) {
-  bool status;
-  decode_serverlist_arg arg;
   pb_istream_t stream =
       pb_istream_from_buffer(GRPC_SLICE_START_PTR(encoded_grpc_grpclb_response),
                              GRPC_SLICE_LENGTH(encoded_grpc_grpclb_response));
   pb_istream_t stream_at_start = stream;
+  grpc_grpclb_serverlist *sl = gpr_zalloc(sizeof(grpc_grpclb_serverlist));
   grpc_grpclb_response res;
   memset(&res, 0, sizeof(grpc_grpclb_response));
-  memset(&arg, 0, sizeof(decode_serverlist_arg));
-
-  res.server_list.servers.funcs.decode = decode_serverlist;
-  res.server_list.servers.arg = &arg;
-  arg.first_pass = true;
-  status = pb_decode(&stream, grpc_lb_v1_LoadBalanceResponse_fields, &res);
+  // First pass: count number of servers.
+  res.server_list.servers.funcs.decode = count_serverlist;
+  res.server_list.servers.arg = sl;
+  bool status = pb_decode(&stream, grpc_lb_v1_LoadBalanceResponse_fields, &res);
   if (!status) {
+    gpr_free(sl);
     gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(&stream));
     return NULL;
   }
-
-  arg.first_pass = false;
-  status =
-      pb_decode(&stream_at_start, grpc_lb_v1_LoadBalanceResponse_fields, &res);
-  if (!status) {
-    gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(&stream));
-    return NULL;
+  // Second pass: populate servers.
+  if (sl->num_servers > 0) {
+    sl->servers = gpr_zalloc(sizeof(grpc_grpclb_server *) * sl->num_servers);
+    decode_serverlist_arg decode_arg;
+    memset(&decode_arg, 0, sizeof(decode_arg));
+    decode_arg.serverlist = sl;
+    res.server_list.servers.funcs.decode = decode_serverlist;
+    res.server_list.servers.arg = &decode_arg;
+    status = pb_decode(&stream_at_start, grpc_lb_v1_LoadBalanceResponse_fields,
+                       &res);
+    if (!status) {
+      grpc_grpclb_destroy_serverlist(sl);
+      gpr_log(GPR_ERROR, "nanopb error: %s", PB_GET_ERROR(&stream));
+      return NULL;
+    }
   }
-
-  grpc_grpclb_serverlist *sl = gpr_zalloc(sizeof(grpc_grpclb_serverlist));
-  sl->num_servers = arg.num_servers;
-  sl->servers = arg.servers;
   if (res.server_list.has_expiration_interval) {
     sl->expiration_interval = res.server_list.expiration_interval;
   }
@@ -228,7 +210,7 @@ grpc_grpclb_serverlist *grpc_grpclb_serverlist_copy(
 
 bool grpc_grpclb_serverlist_equals(const grpc_grpclb_serverlist *lhs,
                                    const grpc_grpclb_serverlist *rhs) {
-  if ((lhs == NULL) || (rhs == NULL)) {
+  if (lhs == NULL || rhs == NULL) {
     return false;
   }
   if (lhs->num_servers != rhs->num_servers) {
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
index 06873821bd..ef8d563edc 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -51,7 +36,7 @@ typedef grpc_lb_v1_LoadBalanceRequest grpc_grpclb_request;
 typedef grpc_lb_v1_InitialLoadBalanceResponse grpc_grpclb_initial_response;
 typedef grpc_lb_v1_Server grpc_grpclb_server;
 typedef grpc_lb_v1_Duration grpc_grpclb_duration;
-typedef struct grpc_grpclb_serverlist {
+typedef struct {
   grpc_grpclb_server **servers;
   size_t num_servers;
   grpc_grpclb_duration expiration_interval;
diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
index b1c5dfc61c..fd0fb41fb9 100644
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -37,11 +22,15 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
+#include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/transport/connectivity_state.h"
 
+grpc_tracer_flag grpc_lb_pick_first_trace =
+    GRPC_TRACER_INITIALIZER(false, "pick_first");
+
 typedef struct pending_pick {
   struct pending_pick *next;
   uint32_t initial_metadata_flags;
@@ -54,7 +43,9 @@ typedef struct {
   grpc_lb_policy base;
   /** all our subchannels */
   grpc_subchannel **subchannels;
+  grpc_subchannel **new_subchannels;
   size_t num_subchannels;
+  size_t num_new_subchannels;
 
   grpc_closure connectivity_changed;
 
@@ -63,10 +54,19 @@ typedef struct {
   /** the selected channel */
   grpc_connected_subchannel *selected;
 
+  /** the subchannel key for \a selected, or NULL if \a selected not set */
+  const grpc_subchannel_key *selected_key;
+
   /** have we started picking? */
-  int started_picking;
+  bool started_picking;
   /** are we shut down? */
-  int shutdown;
+  bool shutdown;
+  /** are we updating the selected subchannel? */
+  bool updating_selected;
+  /** are we updating the subchannel candidates? */
+  bool updating_subchannels;
+  /** args from the latest update received while already updating, or NULL */
+  grpc_lb_policy_args *pending_update_args;
   /** which subchannel are we watching? */
   size_t checking_subchannel;
   /** what is the connectivity of that channel? */
@@ -80,23 +80,31 @@ typedef struct {
 
 static void pf_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
-  size_t i;
   GPR_ASSERT(p->pending_picks == NULL);
-  for (i = 0; i < p->num_subchannels; i++) {
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "pick_first");
+  for (size_t i = 0; i < p->num_subchannels; i++) {
+    GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i], "pick_first_destroy");
   }
   if (p->selected != NULL) {
-    GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected, "picked_first");
+    GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected,
+                                    "picked_first_destroy");
   }
   grpc_connectivity_state_destroy(exec_ctx, &p->state_tracker);
+  if (p->pending_update_args != NULL) {
+    grpc_channel_args_destroy(exec_ctx, p->pending_update_args->args);
+    gpr_free(p->pending_update_args);
+  }
   gpr_free(p->subchannels);
+  gpr_free(p->new_subchannels);
   gpr_free(p);
+  if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+    gpr_log(GPR_DEBUG, "Pick First %p destroyed.", (void *)p);
+  }
 }
 
 static void pf_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   pending_pick *pp;
-  p->shutdown = 1;
+  p->shutdown = true;
   pp = p->pending_picks;
   p->pending_picks = NULL;
   grpc_connectivity_state_set(
@@ -106,7 +114,7 @@ static void pf_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   if (p->selected != NULL) {
     grpc_connected_subchannel_notify_on_state_change(
         exec_ctx, p->selected, NULL, NULL, &p->connectivity_changed);
-  } else if (p->num_subchannels > 0) {
+  } else if (p->num_subchannels > 0 && p->started_picking) {
     grpc_subchannel_notify_on_state_change(
         exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
         &p->connectivity_changed);
@@ -114,7 +122,7 @@ static void pf_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   while (pp != NULL) {
     pending_pick *next = pp->next;
     *pp->target = NULL;
-    grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
     gpr_free(pp);
     pp = next;
   }
@@ -131,7 +139,7 @@ static void pf_cancel_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_closure_sched(exec_ctx, pp->on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick Cancelled", &error, 1));
       gpr_free(pp);
@@ -156,7 +164,7 @@ static void pf_cancel_picks_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
-      grpc_closure_sched(exec_ctx, pp->on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick Cancelled", &error, 1));
       gpr_free(pp);
@@ -169,21 +177,25 @@ static void pf_cancel_picks_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
   GRPC_ERROR_UNREF(error);
 }
 
-static void start_picking(grpc_exec_ctx *exec_ctx, pick_first_lb_policy *p) {
-  p->started_picking = 1;
-  p->checking_subchannel = 0;
-  p->checking_connectivity = GRPC_CHANNEL_IDLE;
-  GRPC_LB_POLICY_WEAK_REF(&p->base, "pick_first_connectivity");
-  grpc_subchannel_notify_on_state_change(
-      exec_ctx, p->subchannels[p->checking_subchannel],
-      p->base.interested_parties, &p->checking_connectivity,
-      &p->connectivity_changed);
+static void start_picking_locked(grpc_exec_ctx *exec_ctx,
+                                 pick_first_lb_policy *p) {
+  p->started_picking = true;
+  if (p->subchannels != NULL) {
+    GPR_ASSERT(p->num_subchannels > 0);
+    p->checking_subchannel = 0;
+    p->checking_connectivity = GRPC_CHANNEL_IDLE;
+    GRPC_LB_POLICY_WEAK_REF(&p->base, "pick_first_connectivity");
+    grpc_subchannel_notify_on_state_change(
+        exec_ctx, p->subchannels[p->checking_subchannel],
+        p->base.interested_parties, &p->checking_connectivity,
+        &p->connectivity_changed);
+  }
 }
 
 static void pf_exit_idle_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   if (!p->started_picking) {
-    start_picking(exec_ctx, p);
+    start_picking_locked(exec_ctx, p);
   }
 }
 
@@ -203,7 +215,7 @@ static int pf_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
   /* No subchannel selected yet, so try again */
   if (!p->started_picking) {
-    start_picking(exec_ctx, p);
+    start_picking_locked(exec_ctx, p);
   }
   pp = gpr_malloc(sizeof(*pp));
   pp->next = p->pending_picks;
@@ -216,30 +228,314 @@ static int pf_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
 static void destroy_subchannels_locked(grpc_exec_ctx *exec_ctx,
                                        pick_first_lb_policy *p) {
-  size_t i;
   size_t num_subchannels = p->num_subchannels;
-  grpc_subchannel **subchannels;
+  grpc_subchannel **subchannels = p->subchannels;
 
-  subchannels = p->subchannels;
   p->num_subchannels = 0;
   p->subchannels = NULL;
   GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "destroy_subchannels");
 
-  for (i = 0; i < num_subchannels; i++) {
+  for (size_t i = 0; i < num_subchannels; i++) {
     GRPC_SUBCHANNEL_UNREF(exec_ctx, subchannels[i], "pick_first");
   }
-
   gpr_free(subchannels);
 }
 
+static grpc_connectivity_state pf_check_connectivity_locked(
+    grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_error **error) {
+  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+  return grpc_connectivity_state_get(&p->state_tracker, error);
+}
+
+static void pf_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
+                                             grpc_lb_policy *pol,
+                                             grpc_connectivity_state *current,
+                                             grpc_closure *notify) {
+  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+  grpc_connectivity_state_notify_on_state_change(exec_ctx, &p->state_tracker,
+                                                 current, notify);
+}
+
+static void pf_ping_one_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
+                               grpc_closure *closure) {
+  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
+  if (p->selected) {
+    grpc_connected_subchannel_ping(exec_ctx, p->selected, closure);
+  } else {
+    GRPC_CLOSURE_SCHED(exec_ctx, closure,
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
+  }
+}
+
+/* unsubscribe all subchannels */
+static void stop_connectivity_watchers(grpc_exec_ctx *exec_ctx,
+                                       pick_first_lb_policy *p) {
+  if (p->num_subchannels > 0) {
+    GPR_ASSERT(p->selected == NULL);
+    if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+      gpr_log(GPR_DEBUG, "Pick First %p unsubscribing from subchannel %p",
+              (void *)p, (void *)p->subchannels[p->checking_subchannel]);
+    }
+    grpc_subchannel_notify_on_state_change(
+        exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
+        &p->connectivity_changed);
+    p->updating_subchannels = true;
+  } else if (p->selected != NULL) {
+    if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+      gpr_log(GPR_DEBUG,
+              "Pick First %p unsubscribing from selected subchannel %p",
+              (void *)p, (void *)p->selected);
+    }
+    grpc_connected_subchannel_notify_on_state_change(
+        exec_ctx, p->selected, NULL, NULL, &p->connectivity_changed);
+    p->updating_selected = true;
+  }
+}
+
+/* true upon success */
+static void pf_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                             const grpc_lb_policy_args *args) {
+  pick_first_lb_policy *p = (pick_first_lb_policy *)policy;
+  /* Find the number of backend addresses. We ignore balancer
+   * addresses, since we don't know how to handle them. */
+  const grpc_arg *arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+  if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
+    if (p->subchannels == NULL) {
+      // If we don't have a current subchannel list, go into TRANSIENT FAILURE.
+      grpc_connectivity_state_set(
+          exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing update in args"),
+          "pf_update_missing");
+    } else {
+      // otherwise, keep using the current subchannel list (ignore this update).
+      gpr_log(GPR_ERROR,
+              "No valid LB addresses channel arg for Pick First %p update, "
+              "ignoring.",
+              (void *)p);
+    }
+    return;
+  }
+  const grpc_lb_addresses *addresses = arg->value.pointer.p;
+  size_t num_addrs = 0;
+  for (size_t i = 0; i < addresses->num_addresses; i++) {
+    if (!addresses->addresses[i].is_balancer) ++num_addrs;
+  }
+  if (num_addrs == 0) {
+    // Empty update. Unsubscribe from all current subchannels and put the
+    // channel in TRANSIENT_FAILURE.
+    grpc_connectivity_state_set(
+        exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Empty update"),
+        "pf_update_empty");
+    stop_connectivity_watchers(exec_ctx, p);
+    return;
+  }
+  if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+    gpr_log(GPR_INFO, "Pick First %p received update with %lu addresses",
+            (void *)p, (unsigned long)num_addrs);
+  }
+  grpc_subchannel_args *sc_args = gpr_zalloc(sizeof(*sc_args) * num_addrs);
+  /* We remove the following keys in order for subchannel keys belonging to
+   * subchannels point to the same address to match. */
+  static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS,
+                                         GRPC_ARG_LB_ADDRESSES};
+  size_t sc_args_count = 0;
+
+  /* Create list of subchannel args for new addresses in \a args. */
+  for (size_t i = 0; i < addresses->num_addresses; i++) {
+    if (addresses->addresses[i].is_balancer) continue;
+    if (addresses->addresses[i].user_data != NULL) {
+      gpr_log(GPR_ERROR,
+              "This LB policy doesn't support user data. It will be ignored");
+    }
+    grpc_arg addr_arg =
+        grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
+    grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
+        args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
+        1);
+    gpr_free(addr_arg.value.string);
+    sc_args[sc_args_count++].args = new_args;
+  }
+
+  /* Check if p->selected is amongst them. If so, we are done. */
+  if (p->selected != NULL) {
+    GPR_ASSERT(p->selected_key != NULL);
+    for (size_t i = 0; i < sc_args_count; i++) {
+      grpc_subchannel_key *ith_sc_key = grpc_subchannel_key_create(&sc_args[i]);
+      const bool found_selected =
+          grpc_subchannel_key_compare(p->selected_key, ith_sc_key) == 0;
+      grpc_subchannel_key_destroy(exec_ctx, ith_sc_key);
+      if (found_selected) {
+        // The currently selected subchannel is in the update: we are done.
+        if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+          gpr_log(GPR_INFO,
+                  "Pick First %p found already selected subchannel %p amongst "
+                  "updates. Update done.",
+                  (void *)p, (void *)p->selected);
+        }
+        for (size_t j = 0; j < sc_args_count; j++) {
+          grpc_channel_args_destroy(exec_ctx,
+                                    (grpc_channel_args *)sc_args[j].args);
+        }
+        gpr_free(sc_args);
+        return;
+      }
+    }
+  }
+  // We only check for already running updates here because if the previous
+  // steps were successful, the update can be considered done without any
+  // interference (ie, no callbacks were scheduled).
+  if (p->updating_selected || p->updating_subchannels) {
+    if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+      gpr_log(GPR_INFO,
+              "Update already in progress for pick first %p. Deferring update.",
+              (void *)p);
+    }
+    if (p->pending_update_args != NULL) {
+      grpc_channel_args_destroy(exec_ctx, p->pending_update_args->args);
+      gpr_free(p->pending_update_args);
+    }
+    p->pending_update_args = gpr_zalloc(sizeof(*p->pending_update_args));
+    p->pending_update_args->client_channel_factory =
+        args->client_channel_factory;
+    p->pending_update_args->args = grpc_channel_args_copy(args->args);
+    p->pending_update_args->combiner = args->combiner;
+    return;
+  }
+  /* Create the subchannels for the new subchannel args/addresses. */
+  grpc_subchannel **new_subchannels =
+      gpr_zalloc(sizeof(*new_subchannels) * sc_args_count);
+  size_t num_new_subchannels = 0;
+  for (size_t i = 0; i < sc_args_count; i++) {
+    grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
+        exec_ctx, args->client_channel_factory, &sc_args[i]);
+    if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+      char *address_uri =
+          grpc_sockaddr_to_uri(&addresses->addresses[i].address);
+      gpr_log(GPR_INFO,
+              "Pick First %p created subchannel %p for address uri %s",
+              (void *)p, (void *)subchannel, address_uri);
+      gpr_free(address_uri);
+    }
+    grpc_channel_args_destroy(exec_ctx, (grpc_channel_args *)sc_args[i].args);
+    if (subchannel != NULL) new_subchannels[num_new_subchannels++] = subchannel;
+  }
+  gpr_free(sc_args);
+  if (num_new_subchannels == 0) {
+    gpr_free(new_subchannels);
+    // Empty update. Unsubscribe from all current subchannels and put the
+    // channel in TRANSIENT_FAILURE.
+    grpc_connectivity_state_set(
+        exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("No valid addresses in update"),
+        "pf_update_no_valid_addresses");
+    stop_connectivity_watchers(exec_ctx, p);
+    return;
+  }
+
+  /* Destroy the current subchannels. Repurpose pf_shutdown/destroy. */
+  stop_connectivity_watchers(exec_ctx, p);
+
+  /* Save new subchannels. The switch over will happen in
+   * pf_connectivity_changed_locked */
+  if (p->updating_selected || p->updating_subchannels) {
+    p->num_new_subchannels = num_new_subchannels;
+    p->new_subchannels = new_subchannels;
+  } else { /* nothing is updating. Get things moving from here */
+    p->num_subchannels = num_new_subchannels;
+    p->subchannels = new_subchannels;
+    p->new_subchannels = NULL;
+    p->num_new_subchannels = 0;
+    if (p->started_picking) {
+      p->checking_subchannel = 0;
+      p->checking_connectivity = GRPC_CHANNEL_IDLE;
+      grpc_subchannel_notify_on_state_change(
+          exec_ctx, p->subchannels[p->checking_subchannel],
+          p->base.interested_parties, &p->checking_connectivity,
+          &p->connectivity_changed);
+    }
+  }
+}
+
 static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                            grpc_error *error) {
   pick_first_lb_policy *p = arg;
   grpc_subchannel *selected_subchannel;
   pending_pick *pp;
 
+  if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+    gpr_log(
+        GPR_DEBUG,
+        "Pick First %p connectivity changed. Updating selected: %d; Updating "
+        "subchannels: %d; Checking %lu index (%lu total); State: %d; ",
+        (void *)p, p->updating_selected, p->updating_subchannels,
+        (unsigned long)p->checking_subchannel,
+        (unsigned long)p->num_subchannels, p->checking_connectivity);
+  }
+  bool restart = false;
+  if (p->updating_selected && error != GRPC_ERROR_NONE) {
+    /* Captured the unsubscription for p->selected */
+    GPR_ASSERT(p->selected != NULL);
+    GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, p->selected,
+                                    "pf_update_connectivity");
+    if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+      gpr_log(GPR_DEBUG, "Pick First %p unreffing selected subchannel %p",
+              (void *)p, (void *)p->selected);
+    }
+    p->updating_selected = false;
+    if (p->num_new_subchannels == 0) {
+      p->selected = NULL;
+      return;
+    }
+    restart = true;
+  }
+  if (p->updating_subchannels && error != GRPC_ERROR_NONE) {
+    /* Captured the unsubscription for the checking subchannel */
+    GPR_ASSERT(p->selected == NULL);
+    for (size_t i = 0; i < p->num_subchannels; i++) {
+      GRPC_SUBCHANNEL_UNREF(exec_ctx, p->subchannels[i],
+                            "pf_update_connectivity");
+      if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+        gpr_log(GPR_DEBUG, "Pick First %p unreffing subchannel %p", (void *)p,
+                (void *)p->subchannels[i]);
+      }
+    }
+    gpr_free(p->subchannels);
+    p->subchannels = NULL;
+    p->num_subchannels = 0;
+    p->updating_subchannels = false;
+    if (p->num_new_subchannels == 0) return;
+    restart = true;
+  }
+  if (restart) {
+    p->selected = NULL;
+    p->selected_key = NULL;
+    GPR_ASSERT(p->new_subchannels != NULL);
+    GPR_ASSERT(p->num_new_subchannels > 0);
+    p->num_subchannels = p->num_new_subchannels;
+    p->subchannels = p->new_subchannels;
+    p->num_new_subchannels = 0;
+    p->new_subchannels = NULL;
+    if (p->started_picking) {
+      /* If we were picking, continue to do so over the new subchannels,
+       * starting from the 0th index. */
+      p->checking_subchannel = 0;
+      p->checking_connectivity = GRPC_CHANNEL_IDLE;
+      /* reuses the weak ref from start_picking_locked */
+      grpc_subchannel_notify_on_state_change(
+          exec_ctx, p->subchannels[p->checking_subchannel],
+          p->base.interested_parties, &p->checking_connectivity,
+          &p->connectivity_changed);
+    }
+    if (p->pending_update_args != NULL) {
+      const grpc_lb_policy_args *args = p->pending_update_args;
+      p->pending_update_args = NULL;
+      pf_update_locked(exec_ctx, &p->base, args);
+    }
+    return;
+  }
   GRPC_ERROR_REF(error);
-
   if (p->shutdown) {
     GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pick_first_connectivity");
     GRPC_ERROR_UNREF(error);
@@ -272,6 +568,13 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
         p->selected = GRPC_CONNECTED_SUBCHANNEL_REF(
             grpc_subchannel_get_connected_subchannel(selected_subchannel),
             "picked_first");
+
+        if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+          gpr_log(GPR_INFO,
+                  "Pick First %p selected subchannel %p (connected %p)",
+                  (void *)p, (void *)selected_subchannel, (void *)p->selected);
+        }
+        p->selected_key = grpc_subchannel_get_key(selected_subchannel);
         /* drop the pick list: we are connected now */
         GRPC_LB_POLICY_WEAK_REF(&p->base, "destroy_subchannels");
         destroy_subchannels_locked(exec_ctx, p);
@@ -279,7 +582,12 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
         while ((pp = p->pending_picks)) {
           p->pending_picks = pp->next;
           *pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(p->selected, "picked");
-          grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
+          if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+            gpr_log(GPR_INFO,
+                    "Servicing pending pick with selected subchannel %p",
+                    (void *)p->selected);
+          }
+          GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
           gpr_free(pp);
         }
         grpc_connected_subchannel_notify_on_state_change(
@@ -290,7 +598,8 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
         p->checking_subchannel =
             (p->checking_subchannel + 1) % p->num_subchannels;
         if (p->checking_subchannel == 0) {
-          /* only trigger transient failure when we've tried all alternatives */
+          /* only trigger transient failure when we've tried all alternatives
+           */
           grpc_connectivity_state_set(
               exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
               GRPC_ERROR_REF(error), "connecting_transient_failure");
@@ -332,7 +641,7 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
           while ((pp = p->pending_picks)) {
             p->pending_picks = pp->next;
             *pp->target = NULL;
-            grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
+            GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
             gpr_free(pp);
           }
           GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base,
@@ -353,32 +662,6 @@ static void pf_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
   GRPC_ERROR_UNREF(error);
 }
 
-static grpc_connectivity_state pf_check_connectivity_locked(
-    grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol, grpc_error **error) {
-  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
-  return grpc_connectivity_state_get(&p->state_tracker, error);
-}
-
-static void pf_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
-                                             grpc_lb_policy *pol,
-                                             grpc_connectivity_state *current,
-                                             grpc_closure *notify) {
-  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
-  grpc_connectivity_state_notify_on_state_change(exec_ctx, &p->state_tracker,
-                                                 current, notify);
-}
-
-static void pf_ping_one_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
-                               grpc_closure *closure) {
-  pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
-  if (p->selected) {
-    grpc_connected_subchannel_ping(exec_ctx, p->selected, closure);
-  } else {
-    grpc_closure_sched(exec_ctx, closure,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
-  }
-}
-
 static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = {
     pf_destroy,
     pf_shutdown_locked,
@@ -388,7 +671,8 @@ static const grpc_lb_policy_vtable pick_first_lb_policy_vtable = {
     pf_ping_one_locked,
     pf_exit_idle_locked,
     pf_check_connectivity_locked,
-    pf_notify_on_state_change_locked};
+    pf_notify_on_state_change_locked,
+    pf_update_locked};
 
 static void pick_first_factory_ref(grpc_lb_policy_factory *factory) {}
 
@@ -398,62 +682,14 @@ static grpc_lb_policy *create_pick_first(grpc_exec_ctx *exec_ctx,
                                          grpc_lb_policy_factory *factory,
                                          grpc_lb_policy_args *args) {
   GPR_ASSERT(args->client_channel_factory != NULL);
-
-  /* Find the number of backend addresses. We ignore balancer
-   * addresses, since we don't know how to handle them. */
-  const grpc_arg *arg =
-      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
-  if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
-    return NULL;
-  }
-  grpc_lb_addresses *addresses = arg->value.pointer.p;
-  size_t num_addrs = 0;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    if (!addresses->addresses[i].is_balancer) ++num_addrs;
-  }
-  if (num_addrs == 0) return NULL;
-
   pick_first_lb_policy *p = gpr_zalloc(sizeof(*p));
-
-  p->subchannels = gpr_zalloc(sizeof(grpc_subchannel *) * num_addrs);
-  grpc_subchannel_args sc_args;
-  size_t subchannel_idx = 0;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    /* Skip balancer addresses, since we only know how to handle backends. */
-    if (addresses->addresses[i].is_balancer) continue;
-
-    if (addresses->addresses[i].user_data != NULL) {
-      gpr_log(GPR_ERROR,
-              "This LB policy doesn't support user data. It will be ignored");
-    }
-
-    static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
-    memset(&sc_args, 0, sizeof(grpc_subchannel_args));
-    grpc_arg addr_arg =
-        grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
-    grpc_channel_args *new_args = grpc_channel_args_copy_and_add_and_remove(
-        args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &addr_arg,
-        1);
-    gpr_free(addr_arg.value.string);
-    sc_args.args = new_args;
-    grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
-        exec_ctx, args->client_channel_factory, &sc_args);
-    grpc_channel_args_destroy(exec_ctx, new_args);
-
-    if (subchannel != NULL) {
-      p->subchannels[subchannel_idx++] = subchannel;
-    }
+  if (GRPC_TRACER_ON(grpc_lb_pick_first_trace)) {
+    gpr_log(GPR_DEBUG, "Pick First %p created.", (void *)p);
   }
-  if (subchannel_idx == 0) {
-    gpr_free(p->subchannels);
-    gpr_free(p);
-    return NULL;
-  }
-  p->num_subchannels = subchannel_idx;
-
+  pf_update_locked(exec_ctx, &p->base, args);
   grpc_lb_policy_init(&p->base, &pick_first_lb_policy_vtable, args->combiner);
-  grpc_closure_init(&p->connectivity_changed, pf_connectivity_changed_locked, p,
-                    grpc_combiner_scheduler(args->combiner, false));
+  GRPC_CLOSURE_INIT(&p->connectivity_changed, pf_connectivity_changed_locked, p,
+                    grpc_combiner_scheduler(args->combiner));
   return &p->base;
 }
 
@@ -472,6 +708,7 @@ static grpc_lb_policy_factory *pick_first_lb_factory_create() {
 
 void grpc_lb_policy_pick_first_init() {
   grpc_register_lb_policy(pick_first_lb_factory_create());
+  grpc_register_tracer(&grpc_lb_pick_first_trace);
 }
 
 void grpc_lb_policy_pick_first_shutdown() {}
diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
index 6e7f410635..341763a4d7 100644
--- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
@@ -1,63 +1,28 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 /** Round Robin Policy.
  *
- * This policy keeps:
- * - A circular list of ready (connected) subchannels, the *readylist*. An empty
- *   readylist consists solely of its root (dummy) node.
- * - A pointer to the last element picked from the readylist, the *lastpick*.
- *   Initially set to point to the readylist's root.
- *
- * Behavior:
- * - When a subchannel connects, it's *prepended* to the readylist's root node.
- *   Ie, if readylist = A <-> B <-> ROOT <-> C
- *                      ^                    ^
- *                      |____________________|
- *   and subchannel D becomes connected, the addition of D to the readylist
- *   results in  readylist = A <-> B <-> D <-> ROOT <-> C
- *                           ^                          ^
- *                           |__________________________|
- * - When a subchannel disconnects, it's removed from the readylist. If the
- *   subchannel being removed was the most recently picked, the *lastpick*
- *   pointer moves to the removed node's previous element. Note that if the
- *   readylist only had one element, this is still legal, as the lastpick would
- *   point to the dummy root node, for an empty readylist.
- * - Upon picking, *lastpick* is updated to point to the returned (connected)
- *   subchannel. Note that it's possible that the selected subchannel becomes
- *   disconnected in the interim between the selection and the actual usage of
- *   the subchannel by the caller.
- */
+ * Before every pick, the \a get_next_ready_subchannel_index_locked function
+ * returns the p->subchannel_list->subchannels index for next subchannel,
+ * respecting the relative
+ * order of the addresses provided upon creation or updates. Note however that
+ * updates will start picking from the beginning of the updated list. */
 
 #include <string.h>
 
@@ -72,9 +37,8 @@
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/static_metadata.h"
 
-typedef struct round_robin_lb_policy round_robin_lb_policy;
-
-grpc_tracer_flag grpc_lb_round_robin_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_lb_round_robin_trace =
+    GRPC_TRACER_INITIALIZER(false, "round_robin");
 
 /** List of entities waiting for a pick.
  *
@@ -99,26 +63,41 @@ typedef struct pending_pick {
   grpc_closure *on_complete;
 } pending_pick;
 
-/** List of subchannels in a connectivity READY state */
-typedef struct ready_list {
-  grpc_subchannel *subchannel;
-  /* references namesake entry in subchannel_data */
-  void *user_data;
-  struct ready_list *next;
-  struct ready_list *prev;
-} ready_list;
+typedef struct rr_subchannel_list rr_subchannel_list;
+typedef struct round_robin_lb_policy {
+  /** base policy: must be first */
+  grpc_lb_policy base;
+
+  rr_subchannel_list *subchannel_list;
+
+  /** have we started picking? */
+  bool started_picking;
+  /** are we shutting down? */
+  bool shutdown;
+  /** List of picks that are waiting on connectivity */
+  pending_pick *pending_picks;
+
+  /** our connectivity state tracker */
+  grpc_connectivity_state_tracker state_tracker;
+
+  /** Index into subchannels for last pick. */
+  size_t last_ready_subchannel_index;
+
+  /** Latest version of the subchannel list.
+   * Subchannel connectivity callbacks will only promote updated subchannel
+   * lists if they equal \a latest_pending_subchannel_list. In other words,
+   * racing callbacks that reference outdated subchannel lists won't perform any
+   * update. */
+  rr_subchannel_list *latest_pending_subchannel_list;
+} round_robin_lb_policy;
 
 typedef struct {
-  /** index within policy->subchannels */
-  size_t index;
-  /** backpointer to owning policy */
-  round_robin_lb_policy *policy;
+  /** backpointer to owning subchannel list */
+  rr_subchannel_list *subchannel_list;
   /** subchannel itself */
   grpc_subchannel *subchannel;
   /** notification that connectivity has changed on subchannel */
   grpc_closure connectivity_changed_closure;
-  /** this subchannels current position in subchannel->ready_list */
-  ready_list *ready_list_node;
   /** last observed connectivity. Not updated by
    * \a grpc_subchannel_notify_on_state_change. Used to determine the previous
    * state while processing the new state in \a rr_connectivity_changed */
@@ -126,201 +105,225 @@ typedef struct {
   /** current connectivity state. Updated by \a
    * grpc_subchannel_notify_on_state_change */
   grpc_connectivity_state curr_connectivity_state;
+  /** connectivity state to be updated by the watcher, not guarded by
+   * the combiner.  Will be moved to curr_connectivity_state inside of
+   * the combiner by rr_connectivity_changed_locked(). */
+  grpc_connectivity_state pending_connectivity_state_unsafe;
   /** the subchannel's target user data */
   void *user_data;
   /** vtable to operate over \a user_data */
   const grpc_lb_user_data_vtable *user_data_vtable;
 } subchannel_data;
 
-struct round_robin_lb_policy {
-  /** base policy: must be first */
-  grpc_lb_policy base;
-
-  /** total number of addresses received at creation time */
-  size_t num_addresses;
+struct rr_subchannel_list {
+  /** backpointer to owning policy */
+  round_robin_lb_policy *policy;
 
   /** all our subchannels */
   size_t num_subchannels;
-  subchannel_data **subchannels;
+  subchannel_data *subchannels;
 
-  /** how many subchannels are in TRANSIENT_FAILURE */
+  /** how many subchannels are in state READY */
+  size_t num_ready;
+  /** how many subchannels are in state TRANSIENT_FAILURE */
   size_t num_transient_failures;
-  /** how many subchannels are IDLE */
+  /** how many subchannels are in state SHUTDOWN */
+  size_t num_shutdown;
+  /** how many subchannels are in state IDLE */
   size_t num_idle;
 
-  /** have we started picking? */
-  int started_picking;
-  /** are we shutting down? */
-  int shutdown;
-  /** List of picks that are waiting on connectivity */
-  pending_pick *pending_picks;
+  /** There will be one ref for each entry in subchannels for which there is a
+   * pending connectivity state watcher callback. */
+  gpr_refcount refcount;
 
-  /** our connectivity state tracker */
-  grpc_connectivity_state_tracker state_tracker;
-
-  /** (Dummy) root of the doubly linked list containing READY subchannels */
-  ready_list ready_list;
-  /** Last pick from the ready list. */
-  ready_list *ready_list_last_pick;
+  /** Is this list shutting down? This may be true due to the shutdown of the
+   * policy itself or because a newer update has arrived while this one hadn't
+   * finished processing. */
+  bool shutting_down;
 };
 
-/** Returns the next subchannel from the connected list or NULL if the list is
- * empty.
- *
- * Note that this function does *not* advance p->ready_list_last_pick. Use \a
- * advance_last_picked_locked() for that. */
-static ready_list *peek_next_connected_locked(const round_robin_lb_policy *p) {
-  ready_list *selected;
-  selected = p->ready_list_last_pick->next;
-
-  while (selected != NULL) {
-    if (selected == &p->ready_list) {
-      GPR_ASSERT(selected->subchannel == NULL);
-      /* skip dummy root */
-      selected = selected->next;
-    } else {
-      GPR_ASSERT(selected->subchannel != NULL);
-      return selected;
-    }
+static rr_subchannel_list *rr_subchannel_list_create(round_robin_lb_policy *p,
+                                                     size_t num_subchannels) {
+  rr_subchannel_list *subchannel_list = gpr_zalloc(sizeof(*subchannel_list));
+  subchannel_list->policy = p;
+  subchannel_list->subchannels =
+      gpr_zalloc(sizeof(subchannel_data) * num_subchannels);
+  subchannel_list->num_subchannels = num_subchannels;
+  gpr_ref_init(&subchannel_list->refcount, 1);
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(GPR_INFO, "[RR %p] Created subchannel list %p for %lu subchannels",
+            (void *)p, (void *)subchannel_list, (unsigned long)num_subchannels);
   }
-  return NULL;
+  return subchannel_list;
 }
 
-/** Advance the \a ready_list picking head. */
-static void advance_last_picked_locked(round_robin_lb_policy *p) {
-  if (p->ready_list_last_pick->next != NULL) { /* non-empty list */
-    p->ready_list_last_pick = p->ready_list_last_pick->next;
-    if (p->ready_list_last_pick == &p->ready_list) {
-      /* skip dummy root */
-      p->ready_list_last_pick = p->ready_list_last_pick->next;
+static void rr_subchannel_list_destroy(grpc_exec_ctx *exec_ctx,
+                                       rr_subchannel_list *subchannel_list) {
+  GPR_ASSERT(subchannel_list->shutting_down);
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(GPR_INFO, "[RR %p] Destroying subchannel_list %p",
+            (void *)subchannel_list->policy, (void *)subchannel_list);
+  }
+  for (size_t i = 0; i < subchannel_list->num_subchannels; i++) {
+    subchannel_data *sd = &subchannel_list->subchannels[i];
+    if (sd->subchannel != NULL) {
+      GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel,
+                            "rr_subchannel_list_destroy");
+    }
+    sd->subchannel = NULL;
+    if (sd->user_data != NULL) {
+      GPR_ASSERT(sd->user_data_vtable != NULL);
+      sd->user_data_vtable->destroy(exec_ctx, sd->user_data);
+      sd->user_data = NULL;
     }
-  } else { /* should be an empty list */
-    GPR_ASSERT(p->ready_list_last_pick == &p->ready_list);
   }
+  gpr_free(subchannel_list->subchannels);
+  gpr_free(subchannel_list);
+}
 
+static void rr_subchannel_list_ref(rr_subchannel_list *subchannel_list,
+                                   const char *reason) {
+  gpr_ref_non_zero(&subchannel_list->refcount);
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG,
-            "[READYLIST, RR: %p] ADVANCED LAST PICK. NOW AT NODE %p (SC %p, "
-            "CSC %p)",
-            (void *)p, (void *)p->ready_list_last_pick,
-            (void *)p->ready_list_last_pick->subchannel,
-            (void *)grpc_subchannel_get_connected_subchannel(
-                p->ready_list_last_pick->subchannel));
+    const gpr_atm count = gpr_atm_acq_load(&subchannel_list->refcount.count);
+    gpr_log(GPR_INFO, "[RR %p] subchannel_list %p REF %lu->%lu (%s)",
+            (void *)subchannel_list->policy, (void *)subchannel_list,
+            (unsigned long)(count - 1), (unsigned long)count, reason);
   }
 }
 
-/** Prepends (relative to the root at p->ready_list) the connected subchannel \a
- * csc to the list of ready subchannels. */
-static ready_list *add_connected_sc_locked(round_robin_lb_policy *p,
-                                           subchannel_data *sd) {
-  ready_list *new_elem = gpr_zalloc(sizeof(ready_list));
-  new_elem->subchannel = sd->subchannel;
-  new_elem->user_data = sd->user_data;
-  if (p->ready_list.prev == NULL) {
-    /* first element */
-    new_elem->next = &p->ready_list;
-    new_elem->prev = &p->ready_list;
-    p->ready_list.next = new_elem;
-    p->ready_list.prev = new_elem;
-  } else {
-    new_elem->next = &p->ready_list;
-    new_elem->prev = p->ready_list.prev;
-    p->ready_list.prev->next = new_elem;
-    p->ready_list.prev = new_elem;
-  }
+static void rr_subchannel_list_unref(grpc_exec_ctx *exec_ctx,
+                                     rr_subchannel_list *subchannel_list,
+                                     const char *reason) {
+  const bool done = gpr_unref(&subchannel_list->refcount);
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG, "[READYLIST] ADDING NODE %p (Conn. SC %p)",
-            (void *)new_elem, (void *)sd->subchannel);
+    const gpr_atm count = gpr_atm_acq_load(&subchannel_list->refcount.count);
+    gpr_log(GPR_INFO, "[RR %p] subchannel_list %p UNREF %lu->%lu (%s)",
+            (void *)subchannel_list->policy, (void *)subchannel_list,
+            (unsigned long)(count + 1), (unsigned long)count, reason);
+  }
+  if (done) {
+    rr_subchannel_list_destroy(exec_ctx, subchannel_list);
   }
-  return new_elem;
 }
 
-/** Removes \a node from the list of connected subchannels */
-static void remove_disconnected_sc_locked(round_robin_lb_policy *p,
-                                          ready_list *node) {
-  if (node == NULL) {
-    return;
+/** Mark \a subchannel_list as discarded. Unsubscribes all its subchannels. The
+ * watcher's callback will ultimately unref \a subchannel_list.  */
+static void rr_subchannel_list_shutdown_and_unref(
+    grpc_exec_ctx *exec_ctx, rr_subchannel_list *subchannel_list,
+    const char *reason) {
+  GPR_ASSERT(!subchannel_list->shutting_down);
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(GPR_DEBUG, "[RR %p] Shutting down subchannel_list %p (%s)",
+            (void *)subchannel_list->policy, (void *)subchannel_list, reason);
   }
-  if (node == p->ready_list_last_pick) {
-    p->ready_list_last_pick = p->ready_list_last_pick->prev;
+  GPR_ASSERT(!subchannel_list->shutting_down);
+  subchannel_list->shutting_down = true;
+  for (size_t i = 0; i < subchannel_list->num_subchannels; i++) {
+    subchannel_data *sd = &subchannel_list->subchannels[i];
+    if (sd->subchannel != NULL) {  // if subchannel isn't shutdown, unsubscribe.
+      if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+        gpr_log(
+            GPR_DEBUG,
+            "[RR %p] Unsubscribing from subchannel %p as part of shutting down "
+            "subchannel_list %p",
+            (void *)subchannel_list->policy, (void *)sd->subchannel,
+            (void *)subchannel_list);
+      }
+      grpc_subchannel_notify_on_state_change(exec_ctx, sd->subchannel, NULL,
+                                             NULL,
+                                             &sd->connectivity_changed_closure);
+    }
   }
+  rr_subchannel_list_unref(exec_ctx, subchannel_list, reason);
+}
 
-  /* removing last item */
-  if (node->next == &p->ready_list && node->prev == &p->ready_list) {
-    GPR_ASSERT(p->ready_list.next == node);
-    GPR_ASSERT(p->ready_list.prev == node);
-    p->ready_list.next = NULL;
-    p->ready_list.prev = NULL;
-  } else {
-    node->prev->next = node->next;
-    node->next->prev = node->prev;
+/** Returns the index into p->subchannel_list->subchannels of the next
+ * subchannel in READY state, or p->subchannel_list->num_subchannels if no
+ * subchannel is READY.
+ *
+ * Note that this function does *not* update p->last_ready_subchannel_index.
+ * The caller must do that if it returns a pick. */
+static size_t get_next_ready_subchannel_index_locked(
+    const round_robin_lb_policy *p) {
+  GPR_ASSERT(p->subchannel_list != NULL);
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(GPR_INFO,
+            "[RR %p] getting next ready subchannel (out of %lu), "
+            "last_ready_subchannel_index=%lu",
+            (void *)p, (unsigned long)p->subchannel_list->num_subchannels,
+            (unsigned long)p->last_ready_subchannel_index);
+  }
+  for (size_t i = 0; i < p->subchannel_list->num_subchannels; ++i) {
+    const size_t index = (i + p->last_ready_subchannel_index + 1) %
+                         p->subchannel_list->num_subchannels;
+    if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+      gpr_log(
+          GPR_DEBUG,
+          "[RR %p] checking subchannel %p, subchannel_list %p, index %lu: "
+          "state=%s",
+          (void *)p, (void *)p->subchannel_list->subchannels[index].subchannel,
+          (void *)p->subchannel_list, (unsigned long)index,
+          grpc_connectivity_state_name(
+              p->subchannel_list->subchannels[index].curr_connectivity_state));
+    }
+    if (p->subchannel_list->subchannels[index].curr_connectivity_state ==
+        GRPC_CHANNEL_READY) {
+      if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+        gpr_log(GPR_DEBUG,
+                "[RR %p] found next ready subchannel (%p) at index %lu of "
+                "subchannel_list %p",
+                (void *)p,
+                (void *)p->subchannel_list->subchannels[index].subchannel,
+                (unsigned long)index, (void *)p->subchannel_list);
+      }
+      return index;
+    }
   }
-
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG, "[READYLIST] REMOVED NODE %p (SC %p)", (void *)node,
-            (void *)node->subchannel);
+    gpr_log(GPR_DEBUG, "[RR %p] no subchannels in ready state", (void *)p);
   }
-
-  node->next = NULL;
-  node->prev = NULL;
-  node->subchannel = NULL;
-
-  gpr_free(node);
+  return p->subchannel_list->num_subchannels;
 }
 
-static bool is_ready_list_empty(round_robin_lb_policy *p) {
-  return p->ready_list.prev == NULL;
+// Sets p->last_ready_subchannel_index to last_ready_index.
+static void update_last_ready_subchannel_index_locked(round_robin_lb_policy *p,
+                                                      size_t last_ready_index) {
+  GPR_ASSERT(last_ready_index < p->subchannel_list->num_subchannels);
+  p->last_ready_subchannel_index = last_ready_index;
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(
+        GPR_DEBUG,
+        "[RR %p] setting last_ready_subchannel_index=%lu (SC %p, CSC %p)",
+        (void *)p, (unsigned long)last_ready_index,
+        (void *)p->subchannel_list->subchannels[last_ready_index].subchannel,
+        (void *)grpc_subchannel_get_connected_subchannel(
+            p->subchannel_list->subchannels[last_ready_index].subchannel));
+  }
 }
 
 static void rr_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  ready_list *elem;
-
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG, "Destroying Round Robin policy at %p", (void *)pol);
-  }
-
-  for (size_t i = 0; i < p->num_subchannels; i++) {
-    subchannel_data *sd = p->subchannels[i];
-    GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "rr_destroy");
-    if (sd->user_data != NULL) {
-      GPR_ASSERT(sd->user_data_vtable != NULL);
-      sd->user_data_vtable->destroy(exec_ctx, sd->user_data);
-    }
-    gpr_free(sd);
+    gpr_log(GPR_DEBUG, "[RR %p] Destroying Round Robin policy at %p",
+            (void *)pol, (void *)pol);
   }
-
   grpc_connectivity_state_destroy(exec_ctx, &p->state_tracker);
-  gpr_free(p->subchannels);
-
-  elem = p->ready_list.next;
-  while (elem != NULL && elem != &p->ready_list) {
-    ready_list *tmp;
-    tmp = elem->next;
-    elem->next = NULL;
-    elem->prev = NULL;
-    elem->subchannel = NULL;
-    gpr_free(elem);
-    elem = tmp;
-  }
-
   gpr_free(p);
 }
 
 static void rr_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  pending_pick *pp;
-  size_t i;
-
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG, "Shutting down Round Robin policy at %p", (void *)pol);
+    gpr_log(GPR_DEBUG, "[RR %p] Shutting down Round Robin policy at %p",
+            (void *)pol, (void *)pol);
   }
-
-  p->shutdown = 1;
+  p->shutdown = true;
+  pending_pick *pp;
   while ((pp = p->pending_picks)) {
     p->pending_picks = pp->next;
     *pp->target = NULL;
-    grpc_closure_sched(
+    GRPC_CLOSURE_SCHED(
         exec_ctx, pp->on_complete,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown"));
     gpr_free(pp);
@@ -328,10 +331,17 @@ static void rr_shutdown_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   grpc_connectivity_state_set(
       exec_ctx, &p->state_tracker, GRPC_CHANNEL_SHUTDOWN,
       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel Shutdown"), "rr_shutdown");
-  for (i = 0; i < p->num_subchannels; i++) {
-    subchannel_data *sd = p->subchannels[i];
-    grpc_subchannel_notify_on_state_change(exec_ctx, sd->subchannel, NULL, NULL,
-                                           &sd->connectivity_changed_closure);
+  const bool latest_is_current =
+      p->subchannel_list == p->latest_pending_subchannel_list;
+  rr_subchannel_list_shutdown_and_unref(exec_ctx, p->subchannel_list,
+                                        "sl_shutdown_rr_shutdown");
+  p->subchannel_list = NULL;
+  if (!latest_is_current && p->latest_pending_subchannel_list != NULL &&
+      !p->latest_pending_subchannel_list->shutting_down) {
+    rr_subchannel_list_shutdown_and_unref(exec_ctx,
+                                          p->latest_pending_subchannel_list,
+                                          "sl_shutdown_pending_rr_shutdown");
+    p->latest_pending_subchannel_list = NULL;
   }
 }
 
@@ -339,14 +349,13 @@ static void rr_cancel_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                                   grpc_connected_subchannel **target,
                                   grpc_error *error) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  pending_pick *pp;
-  pp = p->pending_picks;
+  pending_pick *pp = p->pending_picks;
   p->pending_picks = NULL;
   while (pp != NULL) {
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_closure_sched(exec_ctx, pp->on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick cancelled", &error, 1));
       gpr_free(pp);
@@ -364,15 +373,14 @@ static void rr_cancel_picks_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                                    uint32_t initial_metadata_flags_eq,
                                    grpc_error *error) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  pending_pick *pp;
-  pp = p->pending_picks;
+  pending_pick *pp = p->pending_picks;
   p->pending_picks = NULL;
   while (pp != NULL) {
     pending_pick *next = pp->next;
     if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
       *pp->target = NULL;
-      grpc_closure_sched(exec_ctx, pp->on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete,
                          GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                              "Pick cancelled", &error, 1));
       gpr_free(pp);
@@ -387,21 +395,15 @@ static void rr_cancel_picks_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
 static void start_picking_locked(grpc_exec_ctx *exec_ctx,
                                  round_robin_lb_policy *p) {
-  size_t i;
-  p->started_picking = 1;
-
-  for (i = 0; i < p->num_subchannels; i++) {
-    subchannel_data *sd = p->subchannels[i];
-    /* use some sentinel value outside of the range of grpc_connectivity_state
-     * to signal an undefined previous state. We won't be referring to this
-     * value again and it'll be overwritten after the first call to
-     * rr_connectivity_changed */
-    sd->prev_connectivity_state = GRPC_CHANNEL_INIT;
-    sd->curr_connectivity_state = GRPC_CHANNEL_IDLE;
-    GRPC_LB_POLICY_WEAK_REF(&p->base, "rr_connectivity");
+  p->started_picking = true;
+  for (size_t i = 0; i < p->subchannel_list->num_subchannels; i++) {
+    subchannel_data *sd = &p->subchannel_list->subchannels[i];
+    GRPC_LB_POLICY_WEAK_REF(&p->base, "start_picking_locked");
+    rr_subchannel_list_ref(sd->subchannel_list, "started_picking");
     grpc_subchannel_notify_on_state_change(
         exec_ctx, sd->subchannel, p->base.interested_parties,
-        &sd->curr_connectivity_state, &sd->connectivity_changed_closure);
+        &sd->pending_connectivity_state_unsafe,
+        &sd->connectivity_changed_closure);
   }
 }
 
@@ -418,65 +420,79 @@ static int rr_pick_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                           grpc_call_context_element *context, void **user_data,
                           grpc_closure *on_complete) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  pending_pick *pp;
-  ready_list *selected;
-
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_INFO, "Round Robin %p trying to pick", (void *)pol);
+    gpr_log(GPR_INFO, "[RR %p] Trying to pick", (void *)pol);
   }
-
-  if ((selected = peek_next_connected_locked(p))) {
-    /* readily available, report right away */
-    *target = GRPC_CONNECTED_SUBCHANNEL_REF(
-        grpc_subchannel_get_connected_subchannel(selected->subchannel),
-        "rr_picked");
-
-    if (user_data != NULL) {
-      *user_data = selected->user_data;
-    }
-    if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-      gpr_log(GPR_DEBUG,
-              "[RR PICK] TARGET <-- CONNECTED SUBCHANNEL %p (NODE %p)",
-              (void *)*target, (void *)selected);
-    }
-    /* only advance the last picked pointer if the selection was used */
-    advance_last_picked_locked(p);
-    return 1;
-  } else {
-    /* no pick currently available. Save for later in list of pending picks */
-    if (!p->started_picking) {
-      start_picking_locked(exec_ctx, p);
+  if (p->subchannel_list != NULL) {
+    const size_t next_ready_index = get_next_ready_subchannel_index_locked(p);
+    if (next_ready_index < p->subchannel_list->num_subchannels) {
+      /* readily available, report right away */
+      subchannel_data *sd = &p->subchannel_list->subchannels[next_ready_index];
+      *target = GRPC_CONNECTED_SUBCHANNEL_REF(
+          grpc_subchannel_get_connected_subchannel(sd->subchannel),
+          "rr_picked");
+      if (user_data != NULL) {
+        *user_data = sd->user_data;
+      }
+      if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+        gpr_log(
+            GPR_DEBUG,
+            "[RR %p] Picked target <-- Subchannel %p (connected %p) (sl %p, "
+            "index %lu)",
+            (void *)p, (void *)sd->subchannel, (void *)*target,
+            (void *)sd->subchannel_list, (unsigned long)next_ready_index);
+      }
+      /* only advance the last picked pointer if the selection was used */
+      update_last_ready_subchannel_index_locked(p, next_ready_index);
+      return 1;
     }
-    pp = gpr_malloc(sizeof(*pp));
-    pp->next = p->pending_picks;
-    pp->target = target;
-    pp->on_complete = on_complete;
-    pp->initial_metadata_flags = pick_args->initial_metadata_flags;
-    pp->user_data = user_data;
-    p->pending_picks = pp;
-    return 0;
   }
+  /* no pick currently available. Save for later in list of pending picks */
+  if (!p->started_picking) {
+    start_picking_locked(exec_ctx, p);
+  }
+  pending_pick *pp = gpr_malloc(sizeof(*pp));
+  pp->next = p->pending_picks;
+  pp->target = target;
+  pp->on_complete = on_complete;
+  pp->initial_metadata_flags = pick_args->initial_metadata_flags;
+  pp->user_data = user_data;
+  p->pending_picks = pp;
+  return 0;
 }
 
-static void update_state_counters(subchannel_data *sd) {
-  round_robin_lb_policy *p = sd->policy;
-
-  /* update p->num_transient_failures (resp. p->num_idle): if the previous
-   * state was TRANSIENT_FAILURE (resp. IDLE), decrement
-   * p->num_transient_failures (resp. p->num_idle). */
-  if (sd->prev_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
-    GPR_ASSERT(p->num_transient_failures > 0);
-    --p->num_transient_failures;
+static void update_state_counters_locked(subchannel_data *sd) {
+  rr_subchannel_list *subchannel_list = sd->subchannel_list;
+  if (sd->prev_connectivity_state == GRPC_CHANNEL_READY) {
+    GPR_ASSERT(subchannel_list->num_ready > 0);
+    --subchannel_list->num_ready;
+  } else if (sd->prev_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
+    GPR_ASSERT(subchannel_list->num_transient_failures > 0);
+    --subchannel_list->num_transient_failures;
+  } else if (sd->prev_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
+    GPR_ASSERT(subchannel_list->num_shutdown > 0);
+    --subchannel_list->num_shutdown;
   } else if (sd->prev_connectivity_state == GRPC_CHANNEL_IDLE) {
-    GPR_ASSERT(p->num_idle > 0);
-    --p->num_idle;
+    GPR_ASSERT(subchannel_list->num_idle > 0);
+    --subchannel_list->num_idle;
+  }
+  if (sd->curr_connectivity_state == GRPC_CHANNEL_READY) {
+    ++subchannel_list->num_ready;
+  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
+    ++subchannel_list->num_transient_failures;
+  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
+    ++subchannel_list->num_shutdown;
+  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_IDLE) {
+    ++subchannel_list->num_idle;
   }
 }
 
-/* sd is the subchannel_data associted with the updated subchannel.
- * shutdown_error will only be used upon policy transition to TRANSIENT_FAILURE
- * or SHUTDOWN */
-static grpc_connectivity_state update_lb_connectivity_status(
+/** Sets the policy's connectivity status based on that of the passed-in \a sd
+ * (the subchannel_data associted with the updated subchannel) and the
+ * subchannel list \a sd belongs to (sd->subchannel_list). \a error will only be
+ * used upon policy transition to TRANSIENT_FAILURE or SHUTDOWN. Returns the
+ * connectivity status set. */
+static grpc_connectivity_state update_lb_connectivity_status_locked(
     grpc_exec_ctx *exec_ctx, subchannel_data *sd, grpc_error *error) {
   /* In priority order. The first rule to match terminates the search (ie, if we
    * are on rule n, all previous rules were unfulfilled).
@@ -488,76 +504,167 @@ static grpc_connectivity_state update_lb_connectivity_status(
    *    CHECK: sd->curr_connectivity_state == CONNECTING.
    *
    * 3) RULE: ALL subchannels are SHUTDOWN => policy is SHUTDOWN.
-   *    CHECK: p->num_subchannels = 0.
+   *    CHECK: p->subchannel_list->num_shutdown ==
+   *           p->subchannel_list->num_subchannels.
    *
    * 4) RULE: ALL subchannels are TRANSIENT_FAILURE => policy is
    *    TRANSIENT_FAILURE.
-   *    CHECK: p->num_transient_failures == p->num_subchannels.
+   *    CHECK: p->num_transient_failures == p->subchannel_list->num_subchannels.
    *
    * 5) RULE: ALL subchannels are IDLE => policy is IDLE.
-   *    CHECK: p->num_idle == p->num_subchannels.
+   *    CHECK: p->num_idle == p->subchannel_list->num_subchannels.
    */
-  round_robin_lb_policy *p = sd->policy;
-  if (!is_ready_list_empty(p)) { /* 1) READY */
+  grpc_connectivity_state new_state = sd->curr_connectivity_state;
+  rr_subchannel_list *subchannel_list = sd->subchannel_list;
+  round_robin_lb_policy *p = subchannel_list->policy;
+  if (subchannel_list->num_ready > 0) { /* 1) READY */
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_READY,
                                 GRPC_ERROR_NONE, "rr_ready");
-    return GRPC_CHANNEL_READY;
+    new_state = GRPC_CHANNEL_READY;
   } else if (sd->curr_connectivity_state ==
              GRPC_CHANNEL_CONNECTING) { /* 2) CONNECTING */
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                 GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE,
                                 "rr_connecting");
-    return GRPC_CHANNEL_CONNECTING;
-  } else if (p->num_subchannels == 0) { /* 3) SHUTDOWN */
+    new_state = GRPC_CHANNEL_CONNECTING;
+  } else if (p->subchannel_list->num_shutdown ==
+             p->subchannel_list->num_subchannels) { /* 3) SHUTDOWN */
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                 GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(error),
                                 "rr_shutdown");
-    return GRPC_CHANNEL_SHUTDOWN;
-  } else if (p->num_transient_failures ==
-             p->num_subchannels) { /* 4) TRANSIENT_FAILURE */
+    new_state = GRPC_CHANNEL_SHUTDOWN;
+  } else if (subchannel_list->num_transient_failures ==
+             p->subchannel_list->num_subchannels) { /* 4) TRANSIENT_FAILURE */
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker,
                                 GRPC_CHANNEL_TRANSIENT_FAILURE,
                                 GRPC_ERROR_REF(error), "rr_transient_failure");
-    return GRPC_CHANNEL_TRANSIENT_FAILURE;
-  } else if (p->num_idle == p->num_subchannels) { /* 5) IDLE */
+    new_state = GRPC_CHANNEL_TRANSIENT_FAILURE;
+  } else if (subchannel_list->num_idle ==
+             p->subchannel_list->num_subchannels) { /* 5) IDLE */
     grpc_connectivity_state_set(exec_ctx, &p->state_tracker, GRPC_CHANNEL_IDLE,
                                 GRPC_ERROR_NONE, "rr_idle");
-    return GRPC_CHANNEL_IDLE;
+    new_state = GRPC_CHANNEL_IDLE;
   }
-  /* no change */
-  return sd->curr_connectivity_state;
+  GRPC_ERROR_UNREF(error);
+  return new_state;
 }
 
 static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                            grpc_error *error) {
   subchannel_data *sd = arg;
-  round_robin_lb_policy *p = sd->policy;
-  pending_pick *pp;
-
-  GRPC_ERROR_REF(error);
-
+  round_robin_lb_policy *p = sd->subchannel_list->policy;
+  if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+    gpr_log(
+        GPR_DEBUG,
+        "[RR %p] connectivity changed for subchannel %p, subchannel_list %p: "
+        "prev_state=%s new_state=%s p->shutdown=%d "
+        "sd->subchannel_list->shutting_down=%d error=%s",
+        (void *)p, (void *)sd->subchannel, (void *)sd->subchannel_list,
+        grpc_connectivity_state_name(sd->prev_connectivity_state),
+        grpc_connectivity_state_name(sd->pending_connectivity_state_unsafe),
+        p->shutdown, sd->subchannel_list->shutting_down,
+        grpc_error_string(error));
+  }
+  // If the policy is shutting down, unref and return.
   if (p->shutdown) {
-    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "rr_connectivity");
-    GRPC_ERROR_UNREF(error);
+    rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+                             "pol_shutdown+started_picking");
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "pol_shutdown");
     return;
   }
-  switch (sd->curr_connectivity_state) {
-    case GRPC_CHANNEL_INIT:
-      GPR_UNREACHABLE_CODE(return );
-    case GRPC_CHANNEL_READY:
-      /* add the newly connected subchannel to the list of connected ones.
-       * Note that it goes to the "end of the line". */
-      sd->ready_list_node = add_connected_sc_locked(p, sd);
+  if (sd->subchannel_list->shutting_down && error == GRPC_ERROR_CANCELLED) {
+    // the subchannel list associated with sd has been discarded. This callback
+    // corresponds to the unsubscription. The unrefs correspond to the picking
+    // ref (start_picking_locked or update_started_picking).
+    rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+                             "sl_shutdown+started_picking");
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "sl_shutdown+picking");
+    return;
+  }
+  // Dispose of outdated subchannel lists.
+  if (sd->subchannel_list != p->subchannel_list &&
+      sd->subchannel_list != p->latest_pending_subchannel_list) {
+    // sd belongs to an outdated subchannel_list: get rid of it.
+    rr_subchannel_list_shutdown_and_unref(exec_ctx, sd->subchannel_list,
+                                          "sl_outdated");
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "sl_outdated");
+    return;
+  }
+  // Now that we're inside the combiner, copy the pending connectivity
+  // state (which was set by the connectivity state watcher) to
+  // curr_connectivity_state, which is what we use inside of the combiner.
+  sd->curr_connectivity_state = sd->pending_connectivity_state_unsafe;
+  // Update state counters and determine new overall state.
+  update_state_counters_locked(sd);
+  sd->prev_connectivity_state = sd->curr_connectivity_state;
+  const grpc_connectivity_state new_policy_connectivity_state =
+      update_lb_connectivity_status_locked(exec_ctx, sd, GRPC_ERROR_REF(error));
+  // If the sd's new state is SHUTDOWN, unref the subchannel, and if the new
+  // policy's state is SHUTDOWN, clean up.
+  if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
+    GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "rr_subchannel_shutdown");
+    sd->subchannel = NULL;
+    if (sd->user_data != NULL) {
+      GPR_ASSERT(sd->user_data_vtable != NULL);
+      sd->user_data_vtable->destroy(exec_ctx, sd->user_data);
+      sd->user_data = NULL;
+    }
+    if (new_policy_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
+      // the policy is shutting down. Flush all the pending picks...
+      pending_pick *pp;
+      while ((pp = p->pending_picks)) {
+        p->pending_picks = pp->next;
+        *pp->target = NULL;
+        GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
+        gpr_free(pp);
+      }
+    }
+    rr_subchannel_list_unref(exec_ctx, sd->subchannel_list,
+                             "sd_shutdown+started_picking");
+    // unref the "rr_connectivity_update" weak ref from start_picking.
+    GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base,
+                              "rr_connectivity_sd_shutdown");
+  } else {  // sd not in SHUTDOWN
+    if (sd->curr_connectivity_state == GRPC_CHANNEL_READY) {
+      if (sd->subchannel_list != p->subchannel_list) {
+        // promote sd->subchannel_list to p->subchannel_list.
+        // sd->subchannel_list must be equal to
+        // p->latest_pending_subchannel_list because we have already filtered
+        // for sds belonging to outdated subchannel lists.
+        GPR_ASSERT(sd->subchannel_list == p->latest_pending_subchannel_list);
+        GPR_ASSERT(!sd->subchannel_list->shutting_down);
+        if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+          const unsigned long num_subchannels =
+              p->subchannel_list != NULL
+                  ? (unsigned long)p->subchannel_list->num_subchannels
+                  : 0;
+          gpr_log(GPR_DEBUG,
+                  "[RR %p] phasing out subchannel list %p (size %lu) in favor "
+                  "of %p (size %lu)",
+                  (void *)p, (void *)p->subchannel_list, num_subchannels,
+                  (void *)sd->subchannel_list, num_subchannels);
+        }
+        if (p->subchannel_list != NULL) {
+          // dispose of the current subchannel_list
+          rr_subchannel_list_shutdown_and_unref(exec_ctx, p->subchannel_list,
+                                                "sl_phase_out_shutdown");
+        }
+        p->subchannel_list = p->latest_pending_subchannel_list;
+        p->latest_pending_subchannel_list = NULL;
+      }
       /* at this point we know there's at least one suitable subchannel. Go
        * ahead and pick one and notify the pending suitors in
        * p->pending_picks. This preemtively replicates rr_pick()'s actions. */
-      ready_list *selected = peek_next_connected_locked(p);
-      GPR_ASSERT(selected != NULL);
+      const size_t next_ready_index = get_next_ready_subchannel_index_locked(p);
+      GPR_ASSERT(next_ready_index < p->subchannel_list->num_subchannels);
+      subchannel_data *selected =
+          &p->subchannel_list->subchannels[next_ready_index];
       if (p->pending_picks != NULL) {
-        /* if the selected subchannel is going to be used for the pending
-         * picks, update the last picked pointer */
-        advance_last_picked_locked(p);
+        // if the selected subchannel is going to be used for the pending
+        // picks, update the last picked pointer
+        update_last_ready_subchannel_index_locked(p, next_ready_index);
       }
+      pending_pick *pp;
       while ((pp = p->pending_picks)) {
         p->pending_picks = pp->next;
         *pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(
@@ -568,72 +675,22 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
         }
         if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
           gpr_log(GPR_DEBUG,
-                  "[RR CONN CHANGED] TARGET <-- SUBCHANNEL %p (NODE %p)",
-                  (void *)selected->subchannel, (void *)selected);
+                  "[RR %p] Fulfilling pending pick. Target <-- subchannel %p "
+                  "(subchannel_list %p, index %lu)",
+                  (void *)p, (void *)selected->subchannel,
+                  (void *)p->subchannel_list, (unsigned long)next_ready_index);
         }
-        grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
+        GRPC_CLOSURE_SCHED(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
         gpr_free(pp);
       }
-      update_lb_connectivity_status(exec_ctx, sd, error);
-      sd->prev_connectivity_state = sd->curr_connectivity_state;
-      /* renew notification: reuses the "rr_connectivity" weak ref */
-      grpc_subchannel_notify_on_state_change(
-          exec_ctx, sd->subchannel, p->base.interested_parties,
-          &sd->curr_connectivity_state, &sd->connectivity_changed_closure);
-      break;
-    case GRPC_CHANNEL_IDLE:
-      ++p->num_idle;
-    /* fallthrough */
-    case GRPC_CHANNEL_CONNECTING:
-      update_state_counters(sd);
-      update_lb_connectivity_status(exec_ctx, sd, error);
-      sd->prev_connectivity_state = sd->curr_connectivity_state;
-      /* renew notification: reuses the "rr_connectivity" weak ref */
-      grpc_subchannel_notify_on_state_change(
-          exec_ctx, sd->subchannel, p->base.interested_parties,
-          &sd->curr_connectivity_state, &sd->connectivity_changed_closure);
-      break;
-    case GRPC_CHANNEL_TRANSIENT_FAILURE:
-      ++p->num_transient_failures;
-      /* remove from ready list if still present */
-      if (sd->ready_list_node != NULL) {
-        remove_disconnected_sc_locked(p, sd->ready_list_node);
-        sd->ready_list_node = NULL;
-      }
-      update_lb_connectivity_status(exec_ctx, sd, error);
-      sd->prev_connectivity_state = sd->curr_connectivity_state;
-      /* renew notification: reuses the "rr_connectivity" weak ref */
-      grpc_subchannel_notify_on_state_change(
-          exec_ctx, sd->subchannel, p->base.interested_parties,
-          &sd->curr_connectivity_state, &sd->connectivity_changed_closure);
-      break;
-    case GRPC_CHANNEL_SHUTDOWN:
-      update_state_counters(sd);
-      if (sd->ready_list_node != NULL) {
-        remove_disconnected_sc_locked(p, sd->ready_list_node);
-        sd->ready_list_node = NULL;
-      }
-      --p->num_subchannels;
-      GPR_SWAP(subchannel_data *, p->subchannels[sd->index],
-               p->subchannels[p->num_subchannels]);
-      GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "rr_subchannel_shutdown");
-      p->subchannels[sd->index]->index = sd->index;
-      if (update_lb_connectivity_status(exec_ctx, sd, error) ==
-          GRPC_CHANNEL_SHUTDOWN) {
-        /* the policy is shutting down. Flush all the pending picks... */
-        while ((pp = p->pending_picks)) {
-          p->pending_picks = pp->next;
-          *pp->target = NULL;
-          grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
-          gpr_free(pp);
-        }
-      }
-      gpr_free(sd);
-      /* unref the "rr_connectivity" weak ref from start_picking */
-      GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base, "rr_connectivity");
-      break;
+    }
+    /* renew notification: reuses the "rr_connectivity_update" weak ref on the
+     * policy as well as the sd->subchannel_list ref. */
+    grpc_subchannel_notify_on_state_change(
+        exec_ctx, sd->subchannel, p->base.interested_parties,
+        &sd->pending_connectivity_state_unsafe,
+        &sd->connectivity_changed_closure);
   }
-  GRPC_ERROR_UNREF(error);
 }
 
 static grpc_connectivity_state rr_check_connectivity_locked(
@@ -654,66 +711,85 @@ static void rr_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
 static void rr_ping_one_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                                grpc_closure *closure) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
-  ready_list *selected;
-  grpc_connected_subchannel *target;
-  if ((selected = peek_next_connected_locked(p))) {
-    target = GRPC_CONNECTED_SUBCHANNEL_REF(
+  const size_t next_ready_index = get_next_ready_subchannel_index_locked(p);
+  if (next_ready_index < p->subchannel_list->num_subchannels) {
+    subchannel_data *selected =
+        &p->subchannel_list->subchannels[next_ready_index];
+    grpc_connected_subchannel *target = GRPC_CONNECTED_SUBCHANNEL_REF(
         grpc_subchannel_get_connected_subchannel(selected->subchannel),
         "rr_picked");
     grpc_connected_subchannel_ping(exec_ctx, target, closure);
     GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, target, "rr_picked");
   } else {
-    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+    GRPC_CLOSURE_SCHED(exec_ctx, closure, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                                               "Round Robin not connected"));
   }
 }
 
-static const grpc_lb_policy_vtable round_robin_lb_policy_vtable = {
-    rr_destroy,
-    rr_shutdown_locked,
-    rr_pick_locked,
-    rr_cancel_pick_locked,
-    rr_cancel_picks_locked,
-    rr_ping_one_locked,
-    rr_exit_idle_locked,
-    rr_check_connectivity_locked,
-    rr_notify_on_state_change_locked};
-
-static void round_robin_factory_ref(grpc_lb_policy_factory *factory) {}
-
-static void round_robin_factory_unref(grpc_lb_policy_factory *factory) {}
-
-static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
-                                          grpc_lb_policy_factory *factory,
-                                          grpc_lb_policy_args *args) {
-  GPR_ASSERT(args->client_channel_factory != NULL);
-
-  /* Find the number of backend addresses. We ignore balancer
-   * addresses, since we don't know how to handle them. */
+static void rr_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
+                             const grpc_lb_policy_args *args) {
+  round_robin_lb_policy *p = (round_robin_lb_policy *)policy;
+  /* Find the number of backend addresses. We ignore balancer addresses, since
+   * we don't know how to handle them. */
   const grpc_arg *arg =
       grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
-    return NULL;
+    if (p->subchannel_list == NULL) {
+      // If we don't have a current subchannel list, go into TRANSIENT FAILURE.
+      grpc_connectivity_state_set(
+          exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing update in args"),
+          "rr_update_missing");
+    } else {
+      // otherwise, keep using the current subchannel list (ignore this update).
+      gpr_log(GPR_ERROR,
+              "[RR %p] No valid LB addresses channel arg for update, ignoring.",
+              (void *)p);
+    }
+    return;
   }
   grpc_lb_addresses *addresses = arg->value.pointer.p;
   size_t num_addrs = 0;
   for (size_t i = 0; i < addresses->num_addresses; i++) {
     if (!addresses->addresses[i].is_balancer) ++num_addrs;
   }
-  if (num_addrs == 0) return NULL;
-
-  round_robin_lb_policy *p = gpr_zalloc(sizeof(*p));
-
-  p->num_addresses = num_addrs;
-  p->subchannels = gpr_zalloc(sizeof(*p->subchannels) * num_addrs);
-
+  if (num_addrs == 0) {
+    grpc_connectivity_state_set(
+        exec_ctx, &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Empty update"),
+        "rr_update_empty");
+    if (p->subchannel_list != NULL) {
+      rr_subchannel_list_shutdown_and_unref(exec_ctx, p->subchannel_list,
+                                            "sl_shutdown_empty_update");
+      p->subchannel_list = NULL;
+    }
+    return;
+  }
+  size_t subchannel_index = 0;
+  rr_subchannel_list *subchannel_list = rr_subchannel_list_create(p, num_addrs);
+  if (p->latest_pending_subchannel_list != NULL && p->started_picking) {
+    if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
+      gpr_log(GPR_DEBUG,
+              "[RR %p] Shutting down latest pending subchannel list %p, about "
+              "to be "
+              "replaced by newer latest %p",
+              (void *)p, (void *)p->latest_pending_subchannel_list,
+              (void *)subchannel_list);
+    }
+    rr_subchannel_list_shutdown_and_unref(
+        exec_ctx, p->latest_pending_subchannel_list, "sl_outdated_dont_smash");
+  }
+  p->latest_pending_subchannel_list = subchannel_list;
   grpc_subchannel_args sc_args;
-  size_t subchannel_idx = 0;
+  /* We need to remove the LB addresses in order to be able to compare the
+   * subchannel keys of subchannels from a different batch of addresses. */
+  static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS,
+                                         GRPC_ARG_LB_ADDRESSES};
+  /* Create subchannels for addresses in the update. */
   for (size_t i = 0; i < addresses->num_addresses; i++) {
     /* Skip balancer addresses, since we only know how to handle backends. */
     if (addresses->addresses[i].is_balancer) continue;
-
-    static const char *keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
+    GPR_ASSERT(i < num_addrs);
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
     grpc_arg addr_arg =
         grpc_create_subchannel_address_arg(&addresses->addresses[i].address);
@@ -727,50 +803,86 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
     if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
       char *address_uri =
           grpc_sockaddr_to_uri(&addresses->addresses[i].address);
-      gpr_log(GPR_DEBUG, "Created subchannel %p for address uri %s",
-              (void *)subchannel, address_uri);
+      gpr_log(
+          GPR_DEBUG,
+          "[RR %p] index %lu: Created subchannel %p for address uri %s into "
+          "subchannel_list %p",
+          (void *)p, (unsigned long)subchannel_index, (void *)subchannel,
+          address_uri, (void *)subchannel_list);
       gpr_free(address_uri);
     }
     grpc_channel_args_destroy(exec_ctx, new_args);
 
-    if (subchannel != NULL) {
-      subchannel_data *sd = gpr_zalloc(sizeof(*sd));
-      p->subchannels[subchannel_idx] = sd;
-      sd->policy = p;
-      sd->index = subchannel_idx;
-      sd->subchannel = subchannel;
-      sd->user_data_vtable = addresses->user_data_vtable;
-      if (sd->user_data_vtable != NULL) {
-        sd->user_data =
-            sd->user_data_vtable->copy(addresses->addresses[i].user_data);
-      }
-      ++subchannel_idx;
-      grpc_closure_init(&sd->connectivity_changed_closure,
-                        rr_connectivity_changed_locked, sd,
-                        grpc_combiner_scheduler(args->combiner, false));
+    subchannel_data *sd = &subchannel_list->subchannels[subchannel_index++];
+    sd->subchannel_list = subchannel_list;
+    sd->subchannel = subchannel;
+    GRPC_CLOSURE_INIT(&sd->connectivity_changed_closure,
+                      rr_connectivity_changed_locked, sd,
+                      grpc_combiner_scheduler(args->combiner));
+    /* use some sentinel value outside of the range of
+     * grpc_connectivity_state to signal an undefined previous state. We
+     * won't be referring to this value again and it'll be overwritten after
+     * the first call to rr_connectivity_changed_locked */
+    sd->prev_connectivity_state = GRPC_CHANNEL_INIT;
+    sd->curr_connectivity_state = GRPC_CHANNEL_IDLE;
+    sd->user_data_vtable = addresses->user_data_vtable;
+    if (sd->user_data_vtable != NULL) {
+      sd->user_data =
+          sd->user_data_vtable->copy(addresses->addresses[i].user_data);
+    }
+    if (p->started_picking) {
+      rr_subchannel_list_ref(sd->subchannel_list, "update_started_picking");
+      GRPC_LB_POLICY_WEAK_REF(&p->base, "rr_connectivity_update");
+      /* 2. Watch every new subchannel. A subchannel list becomes active the
+       * moment one of its subchannels is READY. At that moment, we swap
+       * p->subchannel_list for sd->subchannel_list, provided the subchannel
+       * list is still valid (ie, isn't shutting down) */
+      grpc_subchannel_notify_on_state_change(
+          exec_ctx, sd->subchannel, p->base.interested_parties,
+          &sd->pending_connectivity_state_unsafe,
+          &sd->connectivity_changed_closure);
     }
   }
-  if (subchannel_idx == 0) {
-    /* couldn't create any subchannel. Bail out */
-    gpr_free(p->subchannels);
-    gpr_free(p);
-    return NULL;
+  if (!p->started_picking) {
+    // The policy isn't picking yet. Save the update for later, disposing of
+    // previous version if any.
+    if (p->subchannel_list != NULL) {
+      rr_subchannel_list_shutdown_and_unref(exec_ctx, p->subchannel_list,
+                                            "rr_update_before_started_picking");
+    }
+    p->subchannel_list = subchannel_list;
+    p->latest_pending_subchannel_list = NULL;
   }
-  p->num_subchannels = subchannel_idx;
+}
 
-  /* The (dummy node) root of the ready list */
-  p->ready_list.subchannel = NULL;
-  p->ready_list.prev = NULL;
-  p->ready_list.next = NULL;
-  p->ready_list_last_pick = &p->ready_list;
+static const grpc_lb_policy_vtable round_robin_lb_policy_vtable = {
+    rr_destroy,
+    rr_shutdown_locked,
+    rr_pick_locked,
+    rr_cancel_pick_locked,
+    rr_cancel_picks_locked,
+    rr_ping_one_locked,
+    rr_exit_idle_locked,
+    rr_check_connectivity_locked,
+    rr_notify_on_state_change_locked,
+    rr_update_locked};
+
+static void round_robin_factory_ref(grpc_lb_policy_factory *factory) {}
+
+static void round_robin_factory_unref(grpc_lb_policy_factory *factory) {}
 
+static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
+                                          grpc_lb_policy_factory *factory,
+                                          grpc_lb_policy_args *args) {
+  GPR_ASSERT(args->client_channel_factory != NULL);
+  round_robin_lb_policy *p = gpr_zalloc(sizeof(*p));
+  rr_update_locked(exec_ctx, &p->base, args);
   grpc_lb_policy_init(&p->base, &round_robin_lb_policy_vtable, args->combiner);
   grpc_connectivity_state_init(&p->state_tracker, GRPC_CHANNEL_IDLE,
                                "round_robin");
-
   if (GRPC_TRACER_ON(grpc_lb_round_robin_trace)) {
-    gpr_log(GPR_DEBUG, "Created RR policy at %p with %lu subchannels",
-            (void *)p, (unsigned long)p->num_subchannels);
+    gpr_log(GPR_DEBUG, "[RR %p] Created with %lu subchannels", (void *)p,
+            (unsigned long)p->subchannel_list->num_subchannels);
   }
   return &p->base;
 }
@@ -790,7 +902,7 @@ static grpc_lb_policy_factory *round_robin_lb_factory_create() {
 
 void grpc_lb_policy_round_robin_init() {
   grpc_register_lb_policy(round_robin_lb_factory_create());
-  grpc_register_tracer("round_robin", &grpc_lb_round_robin_trace);
+  grpc_register_tracer(&grpc_lb_round_robin_trace);
 }
 
 void grpc_lb_policy_round_robin_shutdown() {}
diff --git a/src/core/ext/filters/client_channel/lb_policy_factory.c b/src/core/ext/filters/client_channel/lb_policy_factory.c
index 89b8bf8951..538d8d65ed 100644
--- a/src/core/ext/filters/client_channel/lb_policy_factory.c
+++ b/src/core/ext/filters/client_channel/lb_policy_factory.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -153,12 +138,8 @@ static const grpc_arg_pointer_vtable lb_addresses_arg_vtable = {
 
 grpc_arg grpc_lb_addresses_create_channel_arg(
     const grpc_lb_addresses* addresses) {
-  grpc_arg arg;
-  arg.type = GRPC_ARG_POINTER;
-  arg.key = GRPC_ARG_LB_ADDRESSES;
-  arg.value.pointer.p = (void*)addresses;
-  arg.value.pointer.vtable = &lb_addresses_arg_vtable;
-  return arg;
+  return grpc_channel_arg_pointer_create(
+      GRPC_ARG_LB_ADDRESSES, (void*)addresses, &lb_addresses_arg_vtable);
 }
 
 grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
diff --git a/src/core/ext/filters/client_channel/lb_policy_factory.h b/src/core/ext/filters/client_channel/lb_policy_factory.h
index 9d6c0fc139..9d9fb143df 100644
--- a/src/core/ext/filters/client_channel/lb_policy_factory.h
+++ b/src/core/ext/filters/client_channel/lb_policy_factory.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -118,11 +103,11 @@ grpc_lb_addresses *grpc_lb_addresses_find_channel_arg(
     const grpc_channel_args *channel_args);
 
 /** Arguments passed to LB policies. */
-typedef struct grpc_lb_policy_args {
+struct grpc_lb_policy_args {
   grpc_client_channel_factory *client_channel_factory;
   grpc_channel_args *args;
   grpc_combiner *combiner;
-} grpc_lb_policy_args;
+};
 
 struct grpc_lb_policy_factory_vtable {
   void (*ref)(grpc_lb_policy_factory *factory);
diff --git a/src/core/ext/filters/client_channel/lb_policy_registry.c b/src/core/ext/filters/client_channel/lb_policy_registry.c
index 1376673bca..f2460f8304 100644
--- a/src/core/ext/filters/client_channel/lb_policy_registry.c
+++ b/src/core/ext/filters/client_channel/lb_policy_registry.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/lb_policy_registry.h b/src/core/ext/filters/client_channel/lb_policy_registry.h
index dfdec1347f..f5995687cf 100644
--- a/src/core/ext/filters/client_channel/lb_policy_registry.h
+++ b/src/core/ext/filters/client_channel/lb_policy_registry.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/parse_address.c b/src/core/ext/filters/client_channel/parse_address.c
index edc6ce697d..2152b5a1e9 100644
--- a/src/core/ext/filters/client_channel/parse_address.c
+++ b/src/core/ext/filters/client_channel/parse_address.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -57,11 +42,11 @@ bool grpc_parse_unix(const grpc_uri *uri,
   struct sockaddr_un *un = (struct sockaddr_un *)resolved_addr->addr;
   const size_t maxlen = sizeof(un->sun_path);
   const size_t path_len = strnlen(uri->path, maxlen);
-  if (path_len == maxlen) return 0;
+  if (path_len == maxlen) return false;
   un->sun_family = AF_UNIX;
   strcpy(un->sun_path, uri->path);
   resolved_addr->len = sizeof(*un);
-  return 1;
+  return true;
 }
 
 #else /* GRPC_HAVE_UNIX_SOCKET */
@@ -73,74 +58,65 @@ bool grpc_parse_unix(const grpc_uri *uri,
 
 #endif /* GRPC_HAVE_UNIX_SOCKET */
 
-bool grpc_parse_ipv4(const grpc_uri *uri,
-                     grpc_resolved_address *resolved_addr) {
-  if (strcmp("ipv4", uri->scheme) != 0) {
-    gpr_log(GPR_ERROR, "Expected 'ipv4' scheme, got '%s'", uri->scheme);
-    return false;
-  }
-  const char *host_port = uri->path;
+bool grpc_parse_ipv4_hostport(const char *hostport, grpc_resolved_address *addr,
+                              bool log_errors) {
+  bool success = false;
+  // Split host and port.
   char *host;
   char *port;
-  int port_num;
-  bool result = false;
-  struct sockaddr_in *in = (struct sockaddr_in *)resolved_addr->addr;
-
-  if (*host_port == '/') ++host_port;
-  if (!gpr_split_host_port(host_port, &host, &port)) {
-    return false;
-  }
-
-  memset(resolved_addr, 0, sizeof(grpc_resolved_address));
-  resolved_addr->len = sizeof(struct sockaddr_in);
+  if (!gpr_split_host_port(hostport, &host, &port)) return false;
+  // Parse IP address.
+  memset(addr, 0, sizeof(*addr));
+  addr->len = sizeof(struct sockaddr_in);
+  struct sockaddr_in *in = (struct sockaddr_in *)addr->addr;
   in->sin_family = AF_INET;
   if (inet_pton(AF_INET, host, &in->sin_addr) == 0) {
-    gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
+    if (log_errors) gpr_log(GPR_ERROR, "invalid ipv4 address: '%s'", host);
     goto done;
   }
-
-  if (port != NULL) {
-    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
-        port_num > 65535) {
-      gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
-      goto done;
-    }
-    in->sin_port = htons((uint16_t)port_num);
-  } else {
-    gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
+  // Parse port.
+  if (port == NULL) {
+    if (log_errors) gpr_log(GPR_ERROR, "no port given for ipv4 scheme");
     goto done;
   }
-
-  result = true;
+  int port_num;
+  if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 || port_num > 65535) {
+    if (log_errors) gpr_log(GPR_ERROR, "invalid ipv4 port: '%s'", port);
+    goto done;
+  }
+  in->sin_port = htons((uint16_t)port_num);
+  success = true;
 done:
   gpr_free(host);
   gpr_free(port);
-  return result;
+  return success;
 }
 
-bool grpc_parse_ipv6(const grpc_uri *uri,
+bool grpc_parse_ipv4(const grpc_uri *uri,
                      grpc_resolved_address *resolved_addr) {
-  if (strcmp("ipv6", uri->scheme) != 0) {
-    gpr_log(GPR_ERROR, "Expected 'ipv6' scheme, got '%s'", uri->scheme);
+  if (strcmp("ipv4", uri->scheme) != 0) {
+    gpr_log(GPR_ERROR, "Expected 'ipv4' scheme, got '%s'", uri->scheme);
     return false;
   }
   const char *host_port = uri->path;
-  char *host;
-  char *port;
-  int port_num;
-  int result = 0;
-  struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)resolved_addr->addr;
-
   if (*host_port == '/') ++host_port;
-  if (!gpr_split_host_port(host_port, &host, &port)) {
-    return 0;
-  }
+  return grpc_parse_ipv4_hostport(host_port, resolved_addr,
+                                  true /* log_errors */);
+}
 
-  memset(in6, 0, sizeof(*in6));
-  resolved_addr->len = sizeof(*in6);
+bool grpc_parse_ipv6_hostport(const char *hostport, grpc_resolved_address *addr,
+                              bool log_errors) {
+  bool success = false;
+  // Split host and port.
+  char *host;
+  char *port;
+  if (!gpr_split_host_port(hostport, &host, &port)) return false;
+  // Parse IP address.
+  memset(addr, 0, sizeof(*addr));
+  addr->len = sizeof(struct sockaddr_in6);
+  struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr->addr;
   in6->sin6_family = AF_INET6;
-
-  /* Handle the RFC6874 syntax for IPv6 zone identifiers. */
+  // Handle the RFC6874 syntax for IPv6 zone identifiers.
   char *host_end = (char *)gpr_memrchr(host, '%', strlen(host));
   if (host_end != NULL) {
     GPR_ASSERT(host_end >= host);
@@ -159,7 +135,7 @@ bool grpc_parse_ipv6(const grpc_uri *uri,
       gpr_log(GPR_ERROR, "invalid ipv6 scope id: '%s'", host_end + 1);
       goto done;
     }
-    // Handle "sin6_scope_id" being type "u_long". See grpc issue ##10027.
+    // Handle "sin6_scope_id" being type "u_long". See grpc issue #10027.
     in6->sin6_scope_id = sin6_scope_id;
   } else {
     if (inet_pton(AF_INET6, host, &in6->sin6_addr) == 0) {
@@ -167,24 +143,34 @@ bool grpc_parse_ipv6(const grpc_uri *uri,
       goto done;
     }
   }
-
-  if (port != NULL) {
-    if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 ||
-        port_num > 65535) {
-      gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
-      goto done;
-    }
-    in6->sin6_port = htons((uint16_t)port_num);
-  } else {
-    gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
+  // Parse port.
+  if (port == NULL) {
+    if (log_errors) gpr_log(GPR_ERROR, "no port given for ipv6 scheme");
     goto done;
   }
-
-  result = 1;
+  int port_num;
+  if (sscanf(port, "%d", &port_num) != 1 || port_num < 0 || port_num > 65535) {
+    if (log_errors) gpr_log(GPR_ERROR, "invalid ipv6 port: '%s'", port);
+    goto done;
+  }
+  in6->sin6_port = htons((uint16_t)port_num);
+  success = true;
 done:
   gpr_free(host);
   gpr_free(port);
-  return result;
+  return success;
+}
+
+bool grpc_parse_ipv6(const grpc_uri *uri,
+                     grpc_resolved_address *resolved_addr) {
+  if (strcmp("ipv6", uri->scheme) != 0) {
+    gpr_log(GPR_ERROR, "Expected 'ipv6' scheme, got '%s'", uri->scheme);
+    return false;
+  }
+  const char *host_port = uri->path;
+  if (*host_port == '/') ++host_port;
+  return grpc_parse_ipv6_hostport(host_port, resolved_addr,
+                                  true /* log_errors */);
 }
 
 bool grpc_parse_uri(const grpc_uri *uri, grpc_resolved_address *resolved_addr) {
diff --git a/src/core/ext/filters/client_channel/parse_address.h b/src/core/ext/filters/client_channel/parse_address.h
index fa7ea33a00..c90a827da5 100644
--- a/src/core/ext/filters/client_channel/parse_address.h
+++ b/src/core/ext/filters/client_channel/parse_address.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -54,4 +39,10 @@ bool grpc_parse_ipv6(const grpc_uri *uri, grpc_resolved_address *resolved_addr);
 /** Populate \a resolved_addr from \a uri. Returns true upon success. */
 bool grpc_parse_uri(const grpc_uri *uri, grpc_resolved_address *resolved_addr);
 
+/** Parse bare IPv4 or IPv6 "IP:port" strings. */
+bool grpc_parse_ipv4_hostport(const char *hostport, grpc_resolved_address *addr,
+                              bool log_errors);
+bool grpc_parse_ipv6_hostport(const char *hostport, grpc_resolved_address *addr,
+                              bool log_errors);
+
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_PARSE_ADDRESS_H */
diff --git a/src/core/ext/filters/client_channel/proxy_mapper.c b/src/core/ext/filters/client_channel/proxy_mapper.c
index 6dddd3c6da..c6ea5fc680 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper.c
+++ b/src/core/ext/filters/client_channel/proxy_mapper.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/proxy_mapper.h b/src/core/ext/filters/client_channel/proxy_mapper.h
index d0c47d3090..a13861ccaf 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper.h
+++ b/src/core/ext/filters/client_channel/proxy_mapper.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/proxy_mapper_registry.c b/src/core/ext/filters/client_channel/proxy_mapper_registry.c
index 7a39289a84..5f43a0596a 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper_registry.c
+++ b/src/core/ext/filters/client_channel/proxy_mapper_registry.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/proxy_mapper_registry.h b/src/core/ext/filters/client_channel/proxy_mapper_registry.h
index 8b5686d664..99e54d1a78 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper_registry.h
+++ b/src/core/ext/filters/client_channel/proxy_mapper_registry.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/resolver.c b/src/core/ext/filters/client_channel/resolver.c
index cafa2837f3..8401504fcf 100644
--- a/src/core/ext/filters/client_channel/resolver.c
+++ b/src/core/ext/filters/client_channel/resolver.c
@@ -1,39 +1,29 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 #include "src/core/ext/filters/client_channel/resolver.h"
 #include "src/core/lib/iomgr/combiner.h"
 
+#ifndef NDEBUG
+grpc_tracer_flag grpc_trace_resolver_refcount =
+    GRPC_TRACER_INITIALIZER(false, "resolver_refcount");
+#endif
+
 void grpc_resolver_init(grpc_resolver *resolver,
                         const grpc_resolver_vtable *vtable,
                         grpc_combiner *combiner) {
@@ -42,25 +32,30 @@ void grpc_resolver_init(grpc_resolver *resolver,
   gpr_ref_init(&resolver->refs, 1);
 }
 
-#ifdef GRPC_RESOLVER_REFCOUNT_DEBUG
-void grpc_resolver_ref(grpc_resolver *resolver, grpc_closure_list *closure_list,
-                       const char *file, int line, const char *reason) {
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "RESOLVER:%p   ref %d -> %d %s",
-          resolver, (int)resolver->refs.count, (int)resolver->refs.count + 1,
-          reason);
+#ifndef NDEBUG
+void grpc_resolver_ref(grpc_resolver *resolver, const char *file, int line,
+                       const char *reason) {
+  if (GRPC_TRACER_ON(grpc_trace_resolver_refcount)) {
+    gpr_atm old_refs = gpr_atm_no_barrier_load(&resolver->refs.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "RESOLVER:%p   ref %" PRIdPTR " -> %" PRIdPTR " %s", resolver,
+            old_refs, old_refs + 1, reason);
+  }
 #else
 void grpc_resolver_ref(grpc_resolver *resolver) {
 #endif
   gpr_ref(&resolver->refs);
 }
 
-#ifdef GRPC_RESOLVER_REFCOUNT_DEBUG
-void grpc_resolver_unref(grpc_resolver *resolver,
-                         grpc_closure_list *closure_list, const char *file,
-                         int line, const char *reason) {
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "RESOLVER:%p unref %d -> %d %s",
-          resolver, (int)resolver->refs.count, (int)resolver->refs.count - 1,
-          reason);
+#ifndef NDEBUG
+void grpc_resolver_unref(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
+                         const char *file, int line, const char *reason) {
+  if (GRPC_TRACER_ON(grpc_trace_resolver_refcount)) {
+    gpr_atm old_refs = gpr_atm_no_barrier_load(&resolver->refs.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "RESOLVER:%p unref %" PRIdPTR " -> %" PRIdPTR " %s", resolver,
+            old_refs, old_refs - 1, reason);
+  }
 #else
 void grpc_resolver_unref(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) {
 #endif
diff --git a/src/core/ext/filters/client_channel/resolver.h b/src/core/ext/filters/client_channel/resolver.h
index 55f9124b3a..ae9c8f66fe 100644
--- a/src/core/ext/filters/client_channel/resolver.h
+++ b/src/core/ext/filters/client_channel/resolver.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -40,6 +25,10 @@
 typedef struct grpc_resolver grpc_resolver;
 typedef struct grpc_resolver_vtable grpc_resolver_vtable;
 
+#ifndef NDEBUG
+extern grpc_tracer_flag grpc_trace_resolver_refcount;
+#endif
+
 /** \a grpc_resolver provides \a grpc_channel_args objects to its caller */
 struct grpc_resolver {
   const grpc_resolver_vtable *vtable;
@@ -56,17 +45,17 @@ struct grpc_resolver_vtable {
                       grpc_channel_args **result, grpc_closure *on_complete);
 };
 
-#ifdef GRPC_RESOLVER_REFCOUNT_DEBUG
+#ifndef NDEBUG
 #define GRPC_RESOLVER_REF(p, r) grpc_resolver_ref((p), __FILE__, __LINE__, (r))
-#define GRPC_RESOLVER_UNREF(cl, p, r) \
-  grpc_resolver_unref((cl), (p), __FILE__, __LINE__, (r))
+#define GRPC_RESOLVER_UNREF(e, p, r) \
+  grpc_resolver_unref((e), (p), __FILE__, __LINE__, (r))
 void grpc_resolver_ref(grpc_resolver *policy, const char *file, int line,
                        const char *reason);
-void grpc_resolver_unref(grpc_resolver *policy, grpc_closure_list *closure_list,
+void grpc_resolver_unref(grpc_exec_ctx *exec_ctx, grpc_resolver *policy,
                          const char *file, int line, const char *reason);
 #else
 #define GRPC_RESOLVER_REF(p, r) grpc_resolver_ref((p))
-#define GRPC_RESOLVER_UNREF(cl, p, r) grpc_resolver_unref((cl), (p))
+#define GRPC_RESOLVER_UNREF(e, p, r) grpc_resolver_unref((e), (p))
 void grpc_resolver_ref(grpc_resolver *policy);
 void grpc_resolver_unref(grpc_exec_ctx *exec_ctx, grpc_resolver *policy);
 #endif
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
index ffaeeed324..04a7852323 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -61,6 +46,8 @@
 typedef struct {
   /** base class: must be first */
   grpc_resolver base;
+  /** DNS server to use (if not system default) */
+  char *dns_server;
   /** name to resolve (usually the same as target_name) */
   char *name_to_resolve;
   /** default port to use */
@@ -78,6 +65,8 @@ typedef struct {
   grpc_combiner *combiner;
   /** are we currently resolving? */
   bool resolving;
+  /** the pending resolving request */
+  grpc_ares_request *pending_request;
   /** which version of the result have we published? */
   int published_version;
   /** which version of the result is current? */
@@ -95,7 +84,7 @@ typedef struct {
   gpr_backoff backoff_state;
 
   /** currently resolving addresses */
-  grpc_resolved_addresses *addresses;
+  grpc_lb_addresses *lb_addresses;
 } ares_dns_resolver;
 
 static void dns_ares_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *r);
@@ -122,9 +111,12 @@ static void dns_ares_shutdown_locked(grpc_exec_ctx *exec_ctx,
   if (r->have_retry_timer) {
     grpc_timer_cancel(exec_ctx, &r->retry_timer);
   }
+  if (r->pending_request != NULL) {
+    grpc_cancel_ares_request(exec_ctx, r->pending_request);
+  }
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
-    grpc_closure_sched(
+    GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
     r->next_completion = NULL;
@@ -158,20 +150,14 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_channel_args *result = NULL;
   GPR_ASSERT(r->resolving);
   r->resolving = false;
-  if (r->addresses != NULL) {
-    grpc_lb_addresses *addresses = grpc_lb_addresses_create(
-        r->addresses->naddrs, NULL /* user_data_vtable */);
-    for (size_t i = 0; i < r->addresses->naddrs; ++i) {
-      grpc_lb_addresses_set_address(
-          addresses, i, &r->addresses->addrs[i].addr,
-          r->addresses->addrs[i].len, false /* is_balancer */,
-          NULL /* balancer_name */, NULL /* user_data */);
-    }
-    grpc_arg new_arg = grpc_lb_addresses_create_channel_arg(addresses);
+  r->pending_request = NULL;
+  if (r->lb_addresses != NULL) {
+    grpc_arg new_arg = grpc_lb_addresses_create_channel_arg(r->lb_addresses);
     result = grpc_channel_args_copy_and_add(r->channel_args, &new_arg, 1);
-    grpc_resolved_addresses_destroy(r->addresses);
-    grpc_lb_addresses_destroy(exec_ctx, addresses);
+    grpc_lb_addresses_destroy(exec_ctx, r->lb_addresses);
   } else {
+    const char *msg = grpc_error_string(error);
+    gpr_log(GPR_DEBUG, "dns resolution failed: %s", msg);
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now);
     gpr_timespec timeout = gpr_time_sub(next_try, now);
@@ -220,10 +206,11 @@ static void dns_ares_start_resolving_locked(grpc_exec_ctx *exec_ctx,
   GRPC_RESOLVER_REF(&r->base, "dns-resolving");
   GPR_ASSERT(!r->resolving);
   r->resolving = true;
-  r->addresses = NULL;
-  grpc_resolve_address(exec_ctx, r->name_to_resolve, r->default_port,
-                       r->interested_parties, &r->dns_ares_on_resolved_locked,
-                       &r->addresses);
+  r->lb_addresses = NULL;
+  r->pending_request = grpc_dns_lookup_ares(
+      exec_ctx, r->dns_server, r->name_to_resolve, r->default_port,
+      r->interested_parties, &r->dns_ares_on_resolved_locked, &r->lb_addresses,
+      true /* check_grpclb */);
 }
 
 static void dns_ares_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
@@ -233,7 +220,8 @@ static void dns_ares_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
     *r->target_result = r->resolved_result == NULL
                             ? NULL
                             : grpc_channel_args_copy(r->resolved_result);
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
+    gpr_log(GPR_DEBUG, "dns_ares_maybe_finish_next_locked");
+    GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
     r->published_version = r->resolved_version;
   }
@@ -246,6 +234,7 @@ static void dns_ares_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) {
     grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   grpc_pollset_set_destroy(exec_ctx, r->interested_parties);
+  gpr_free(r->dns_server);
   gpr_free(r->name_to_resolve);
   gpr_free(r->default_port);
   grpc_channel_args_destroy(exec_ctx, r->channel_args);
@@ -255,16 +244,15 @@ static void dns_ares_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) {
 static grpc_resolver *dns_ares_create(grpc_exec_ctx *exec_ctx,
                                       grpc_resolver_args *args,
                                       const char *default_port) {
-  // Get name from args.
+  /* Get name from args. */
   const char *path = args->uri->path;
-  if (0 != strcmp(args->uri->authority, "")) {
-    gpr_log(GPR_ERROR, "authority based dns uri's not supported");
-    return NULL;
-  }
   if (path[0] == '/') ++path;
-  // Create resolver.
+  /* Create resolver. */
   ares_dns_resolver *r = gpr_zalloc(sizeof(ares_dns_resolver));
   grpc_resolver_init(&r->base, &dns_ares_resolver_vtable, args->combiner);
+  if (0 != strcmp(args->uri->authority, "")) {
+    r->dns_server = gpr_strdup(args->uri->authority);
+  }
   r->name_to_resolve = gpr_strdup(path);
   r->default_port = gpr_strdup(default_port);
   r->channel_args = grpc_channel_args_copy(args->args);
@@ -278,12 +266,12 @@ static grpc_resolver *dns_ares_create(grpc_exec_ctx *exec_ctx,
                    GRPC_DNS_RECONNECT_JITTER,
                    GRPC_DNS_MIN_CONNECT_TIMEOUT_SECONDS * 1000,
                    GRPC_DNS_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
-  grpc_closure_init(&r->dns_ares_on_retry_timer_locked,
+  GRPC_CLOSURE_INIT(&r->dns_ares_on_retry_timer_locked,
                     dns_ares_on_retry_timer_locked, r,
-                    grpc_combiner_scheduler(r->base.combiner, false));
-  grpc_closure_init(&r->dns_ares_on_resolved_locked,
+                    grpc_combiner_scheduler(r->base.combiner));
+  GRPC_CLOSURE_INIT(&r->dns_ares_on_resolved_locked,
                     dns_ares_on_resolved_locked, r,
-                    grpc_combiner_scheduler(r->base.combiner, false));
+                    grpc_combiner_scheduler(r->base.combiner));
   return &r->base;
 }
 
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
index aa88940021..386012d2ed 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
@@ -1,41 +1,24 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H
 
-#include <ares.h>
-
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/pollset_set.h"
 
@@ -62,5 +45,9 @@ grpc_error *grpc_ares_ev_driver_create(grpc_ares_ev_driver **ev_driver,
    of ARES_ECANCELLED. */
 void grpc_ares_ev_driver_destroy(grpc_ares_ev_driver *ev_driver);
 
+/* Shutdown all the grpc_fds used by \a ev_driver */
+void grpc_ares_ev_driver_shutdown(grpc_exec_ctx *exec_ctx,
+                                  grpc_ares_ev_driver *ev_driver);
+
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H \
           */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.c
index 1e4f3eb5ab..1ab8295e9e 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.c
@@ -1,39 +1,26 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 #include <grpc/support/port_platform.h>
 #include "src/core/lib/iomgr/port.h"
 #if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET)
 
+#include <ares.h>
+
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
 
 #include <grpc/support/alloc.h>
@@ -114,9 +101,12 @@ static void fd_node_destroy(grpc_exec_ctx *exec_ctx, fd_node *fdn) {
   GPR_ASSERT(!fdn->writable_registered);
   gpr_mu_destroy(&fdn->mu);
   grpc_pollset_set_del_fd(exec_ctx, fdn->ev_driver->pollset_set, fdn->grpc_fd);
-  grpc_fd_shutdown(exec_ctx, fdn->grpc_fd,
-                   GRPC_ERROR_CREATE_FROM_STATIC_STRING("fd node destroyed"));
-  grpc_fd_orphan(exec_ctx, fdn->grpc_fd, NULL, NULL, "c-ares query finished");
+  /* c-ares library has closed the fd inside grpc_fd. This fd may be picked up
+     immediately by another thread, and should not be closed by the following
+     grpc_fd_orphan. To prevent this fd from being closed by grpc_fd_orphan,
+     a fd pointer is provided. */
+  int fd;
+  grpc_fd_orphan(exec_ctx, fdn->grpc_fd, NULL, &fd, "c-ares query finished");
   gpr_free(fdn);
 }
 
@@ -155,6 +145,20 @@ void grpc_ares_ev_driver_destroy(grpc_ares_ev_driver *ev_driver) {
   grpc_ares_ev_driver_unref(ev_driver);
 }
 
+void grpc_ares_ev_driver_shutdown(grpc_exec_ctx *exec_ctx,
+                                  grpc_ares_ev_driver *ev_driver) {
+  gpr_mu_lock(&ev_driver->mu);
+  ev_driver->shutting_down = true;
+  fd_node *fn = ev_driver->fds;
+  while (fn != NULL) {
+    grpc_fd_shutdown(
+        exec_ctx, fn->grpc_fd,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("grpc_ares_ev_driver_shutdown"));
+    fn = fn->next;
+  }
+  gpr_mu_unlock(&ev_driver->mu);
+}
+
 // Search fd in the fd_node list head. This is an O(n) search, the max possible
 // value of n is ARES_GETSOCK_MAXNUM (16). n is typically 1 - 2 in our tests.
 static fd_node *pop_fd_node(fd_node **head, int fd) {
@@ -255,9 +259,9 @@ static void grpc_ares_notify_on_event_locked(grpc_exec_ctx *exec_ctx,
           fdn->readable_registered = false;
           fdn->writable_registered = false;
           gpr_mu_init(&fdn->mu);
-          grpc_closure_init(&fdn->read_closure, on_readable_cb, fdn,
+          GRPC_CLOSURE_INIT(&fdn->read_closure, on_readable_cb, fdn,
                             grpc_schedule_on_exec_ctx);
-          grpc_closure_init(&fdn->write_closure, on_writable_cb, fdn,
+          GRPC_CLOSURE_INIT(&fdn->write_closure, on_writable_cb, fdn,
                             grpc_schedule_on_exec_ctx);
           grpc_pollset_set_add_fd(exec_ctx, ev_driver->pollset_set,
                                   fdn->grpc_fd);
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c
index 09c46a66e0..9065e33613 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -48,7 +33,11 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 #include <grpc/support/useful.h>
+#include <nameser.h>
+
+#include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
+#include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
@@ -57,18 +46,14 @@
 static gpr_once g_basic_init = GPR_ONCE_INIT;
 static gpr_mu g_init_mu;
 
-typedef struct grpc_ares_request {
+struct grpc_ares_request {
+  /** indicates the DNS server to use, if specified */
+  struct ares_addr_port_node dns_server_addr;
   /** following members are set in grpc_resolve_address_ares_impl */
-  /** host to resolve, parsed from the name to resolve */
-  char *host;
-  /** port to fill in sockaddr_in, parsed from the name to resolve */
-  char *port;
-  /** default port to use */
-  char *default_port;
   /** closure to call when the request completes */
   grpc_closure *on_done;
   /** the pointer to receive the resolved addresses */
-  grpc_resolved_addresses **addrs_out;
+  grpc_lb_addresses **lb_addrs_out;
   /** the evernt driver used by this request */
   grpc_ares_ev_driver *ev_driver;
   /** number of ongoing queries */
@@ -80,7 +65,19 @@ typedef struct grpc_ares_request {
   bool success;
   /** the errors explaining the request failure, set in on_done_cb */
   grpc_error *error;
-} grpc_ares_request;
+};
+
+typedef struct grpc_ares_hostbyname_request {
+  /** following members are set in create_hostbyname_request */
+  /** the top-level request instance */
+  grpc_ares_request *parent_request;
+  /** host to resolve, parsed from the name to resolve */
+  char *host;
+  /** port to fill in sockaddr_in, parsed from the name to resolve */
+  uint16_t port;
+  /** is it a grpclb address */
+  bool is_balancer;
+} grpc_ares_hostbyname_request;
 
 static void do_basic_init(void) { gpr_mu_init(&g_init_mu); }
 
@@ -93,6 +90,10 @@ static uint16_t strhtons(const char *port) {
   return htons((unsigned short)atoi(port));
 }
 
+static void grpc_ares_request_ref(grpc_ares_request *r) {
+  gpr_ref(&r->pending_queries);
+}
+
 static void grpc_ares_request_unref(grpc_exec_ctx *exec_ctx,
                                     grpc_ares_request *r) {
   /* If there are no pending queries, invoke on_done callback and destroy the
@@ -106,74 +107,102 @@ static void grpc_ares_request_unref(grpc_exec_ctx *exec_ctx,
          acquire locks in on_done. ares_dns_resolver is using combiner to
          protect resources needed by on_done. */
       grpc_exec_ctx new_exec_ctx = GRPC_EXEC_CTX_INIT;
-      grpc_closure_sched(&new_exec_ctx, r->on_done, r->error);
+      GRPC_CLOSURE_SCHED(&new_exec_ctx, r->on_done, r->error);
       grpc_exec_ctx_finish(&new_exec_ctx);
     } else {
-      grpc_closure_sched(exec_ctx, r->on_done, r->error);
+      GRPC_CLOSURE_SCHED(exec_ctx, r->on_done, r->error);
     }
     gpr_mu_destroy(&r->mu);
     grpc_ares_ev_driver_destroy(r->ev_driver);
-    gpr_free(r->host);
-    gpr_free(r->port);
-    gpr_free(r->default_port);
     gpr_free(r);
   }
 }
 
-static void on_done_cb(void *arg, int status, int timeouts,
-                       struct hostent *hostent) {
-  grpc_ares_request *r = (grpc_ares_request *)arg;
+static grpc_ares_hostbyname_request *create_hostbyname_request(
+    grpc_ares_request *parent_request, char *host, uint16_t port,
+    bool is_balancer) {
+  grpc_ares_hostbyname_request *hr =
+      gpr_zalloc(sizeof(grpc_ares_hostbyname_request));
+  hr->parent_request = parent_request;
+  hr->host = gpr_strdup(host);
+  hr->port = port;
+  hr->is_balancer = is_balancer;
+  grpc_ares_request_ref(parent_request);
+  return hr;
+}
+
+static void destroy_hostbyname_request(grpc_exec_ctx *exec_ctx,
+                                       grpc_ares_hostbyname_request *hr) {
+  grpc_ares_request_unref(exec_ctx, hr->parent_request);
+  gpr_free(hr->host);
+  gpr_free(hr);
+}
+
+static void on_hostbyname_done_cb(void *arg, int status, int timeouts,
+                                  struct hostent *hostent) {
+  grpc_ares_hostbyname_request *hr = (grpc_ares_hostbyname_request *)arg;
+  grpc_ares_request *r = hr->parent_request;
   gpr_mu_lock(&r->mu);
   if (status == ARES_SUCCESS) {
     GRPC_ERROR_UNREF(r->error);
     r->error = GRPC_ERROR_NONE;
     r->success = true;
-    grpc_resolved_addresses **addresses = r->addrs_out;
-    if (*addresses == NULL) {
-      *addresses = gpr_malloc(sizeof(grpc_resolved_addresses));
-      (*addresses)->naddrs = 0;
-      (*addresses)->addrs = NULL;
+    grpc_lb_addresses **lb_addresses = r->lb_addrs_out;
+    if (*lb_addresses == NULL) {
+      *lb_addresses = grpc_lb_addresses_create(0, NULL);
     }
-    size_t prev_naddr = (*addresses)->naddrs;
+    size_t prev_naddr = (*lb_addresses)->num_addresses;
     size_t i;
     for (i = 0; hostent->h_addr_list[i] != NULL; i++) {
     }
-    (*addresses)->naddrs += i;
-    (*addresses)->addrs =
-        gpr_realloc((*addresses)->addrs,
-                    sizeof(grpc_resolved_address) * (*addresses)->naddrs);
-    for (i = prev_naddr; i < (*addresses)->naddrs; i++) {
-      memset(&(*addresses)->addrs[i], 0, sizeof(grpc_resolved_address));
-      if (hostent->h_addrtype == AF_INET6) {
-        (*addresses)->addrs[i].len = sizeof(struct sockaddr_in6);
-        struct sockaddr_in6 *addr =
-            (struct sockaddr_in6 *)&(*addresses)->addrs[i].addr;
-        addr->sin6_family = (sa_family_t)hostent->h_addrtype;
-        addr->sin6_port = strhtons(r->port);
-
-        char output[INET6_ADDRSTRLEN];
-        memcpy(&addr->sin6_addr, hostent->h_addr_list[i - prev_naddr],
-               sizeof(struct in6_addr));
-        ares_inet_ntop(AF_INET6, &addr->sin6_addr, output, INET6_ADDRSTRLEN);
-        gpr_log(GPR_DEBUG,
-                "c-ares resolver gets a AF_INET6 result: \n"
-                "  addr: %s\n  port: %s\n  sin6_scope_id: %d\n",
-                output, r->port, addr->sin6_scope_id);
-      } else {
-        (*addresses)->addrs[i].len = sizeof(struct sockaddr_in);
-        struct sockaddr_in *addr =
-            (struct sockaddr_in *)&(*addresses)->addrs[i].addr;
-        memcpy(&addr->sin_addr, hostent->h_addr_list[i - prev_naddr],
-               sizeof(struct in_addr));
-        addr->sin_family = (sa_family_t)hostent->h_addrtype;
-        addr->sin_port = strhtons(r->port);
-
-        char output[INET_ADDRSTRLEN];
-        ares_inet_ntop(AF_INET, &addr->sin_addr, output, INET_ADDRSTRLEN);
-        gpr_log(GPR_DEBUG,
-                "c-ares resolver gets a AF_INET result: \n"
-                "  addr: %s\n  port: %s\n",
-                output, r->port);
+    (*lb_addresses)->num_addresses += i;
+    (*lb_addresses)->addresses =
+        gpr_realloc((*lb_addresses)->addresses,
+                    sizeof(grpc_lb_address) * (*lb_addresses)->num_addresses);
+    for (i = prev_naddr; i < (*lb_addresses)->num_addresses; i++) {
+      switch (hostent->h_addrtype) {
+        case AF_INET6: {
+          size_t addr_len = sizeof(struct sockaddr_in6);
+          struct sockaddr_in6 addr;
+          memset(&addr, 0, addr_len);
+          memcpy(&addr.sin6_addr, hostent->h_addr_list[i - prev_naddr],
+                 sizeof(struct in6_addr));
+          addr.sin6_family = (sa_family_t)hostent->h_addrtype;
+          addr.sin6_port = hr->port;
+          grpc_lb_addresses_set_address(
+              *lb_addresses, i, &addr, addr_len,
+              hr->is_balancer /* is_balancer */,
+              hr->is_balancer ? strdup(hr->host) : NULL /* balancer_name */,
+              NULL /* user_data */);
+          char output[INET6_ADDRSTRLEN];
+          ares_inet_ntop(AF_INET6, &addr.sin6_addr, output, INET6_ADDRSTRLEN);
+          gpr_log(GPR_DEBUG,
+                  "c-ares resolver gets a AF_INET6 result: \n"
+                  "  addr: %s\n  port: %d\n  sin6_scope_id: %d\n",
+                  output, ntohs(hr->port), addr.sin6_scope_id);
+          break;
+        }
+        case AF_INET: {
+          size_t addr_len = sizeof(struct sockaddr_in);
+          struct sockaddr_in addr;
+          memset(&addr, 0, addr_len);
+          memcpy(&addr.sin_addr, hostent->h_addr_list[i - prev_naddr],
+                 sizeof(struct in_addr));
+          addr.sin_family = (sa_family_t)hostent->h_addrtype;
+          addr.sin_port = hr->port;
+          grpc_lb_addresses_set_address(
+              *lb_addresses, i, &addr, addr_len,
+              hr->is_balancer /* is_balancer */,
+              hr->is_balancer ? strdup(hr->host) : NULL /* balancer_name */,
+              NULL /* user_data */);
+          char output[INET_ADDRSTRLEN];
+          ares_inet_ntop(AF_INET, &addr.sin_addr, output, INET_ADDRSTRLEN);
+          gpr_log(GPR_DEBUG,
+                  "c-ares resolver gets a AF_INET result: \n"
+                  "  addr: %s\n  port: %d\n",
+                  output, ntohs(hr->port));
+          break;
+        }
       }
     }
   } else if (!r->success) {
@@ -189,14 +218,59 @@ static void on_done_cb(void *arg, int status, int timeouts,
     }
   }
   gpr_mu_unlock(&r->mu);
-  grpc_ares_request_unref(NULL, r);
+  destroy_hostbyname_request(NULL, hr);
+}
+
+static void on_srv_query_done_cb(void *arg, int status, int timeouts,
+                                 unsigned char *abuf, int alen) {
+  grpc_ares_request *r = (grpc_ares_request *)arg;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  gpr_log(GPR_DEBUG, "on_query_srv_done_cb");
+  if (status == ARES_SUCCESS) {
+    gpr_log(GPR_DEBUG, "on_query_srv_done_cb ARES_SUCCESS");
+    struct ares_srv_reply *reply;
+    const int parse_status = ares_parse_srv_reply(abuf, alen, &reply);
+    if (parse_status == ARES_SUCCESS) {
+      ares_channel *channel = grpc_ares_ev_driver_get_channel(r->ev_driver);
+      for (struct ares_srv_reply *srv_it = reply; srv_it != NULL;
+           srv_it = srv_it->next) {
+        if (grpc_ipv6_loopback_available()) {
+          grpc_ares_hostbyname_request *hr = create_hostbyname_request(
+              r, srv_it->host, htons(srv_it->port), true /* is_balancer */);
+          ares_gethostbyname(*channel, hr->host, AF_INET6,
+                             on_hostbyname_done_cb, hr);
+        }
+        grpc_ares_hostbyname_request *hr = create_hostbyname_request(
+            r, srv_it->host, htons(srv_it->port), true /* is_balancer */);
+        ares_gethostbyname(*channel, hr->host, AF_INET, on_hostbyname_done_cb,
+                           hr);
+        grpc_ares_ev_driver_start(&exec_ctx, r->ev_driver);
+      }
+    }
+    if (reply != NULL) {
+      ares_free_data(reply);
+    }
+  } else if (!r->success) {
+    char *error_msg;
+    gpr_asprintf(&error_msg, "C-ares status is not ARES_SUCCESS: %s",
+                 ares_strerror(status));
+    grpc_error *error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg);
+    gpr_free(error_msg);
+    if (r->error == GRPC_ERROR_NONE) {
+      r->error = error;
+    } else {
+      r->error = grpc_error_add_child(error, r->error);
+    }
+  }
+  grpc_ares_request_unref(&exec_ctx, r);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
-void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
-                                    const char *default_port,
-                                    grpc_pollset_set *interested_parties,
-                                    grpc_closure *on_done,
-                                    grpc_resolved_addresses **addrs) {
+static grpc_ares_request *grpc_dns_lookup_ares_impl(
+    grpc_exec_ctx *exec_ctx, const char *dns_server, const char *name,
+    const char *default_port, grpc_pollset_set *interested_parties,
+    grpc_closure *on_done, grpc_lb_addresses **addrs, bool check_grpclb) {
+  grpc_error *error = GRPC_ERROR_NONE;
   /* TODO(zyc): Enable tracing after #9603 is checked in */
   /* if (grpc_dns_trace) {
       gpr_log(GPR_DEBUG, "resolve_address (blocking): name=%s, default_port=%s",
@@ -208,60 +282,111 @@ void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx, const char *name,
   char *port;
   gpr_split_host_port(name, &host, &port);
   if (host == NULL) {
-    grpc_error *err = grpc_error_set_str(
+    error = grpc_error_set_str(
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("unparseable host:port"),
         GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
-    grpc_closure_sched(exec_ctx, on_done, err);
     goto error_cleanup;
   } else if (port == NULL) {
     if (default_port == NULL) {
-      grpc_error *err = grpc_error_set_str(
+      error = grpc_error_set_str(
           GRPC_ERROR_CREATE_FROM_STATIC_STRING("no port in name"),
           GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
-      grpc_closure_sched(exec_ctx, on_done, err);
       goto error_cleanup;
     }
     port = gpr_strdup(default_port);
   }
 
   grpc_ares_ev_driver *ev_driver;
-  grpc_error *err = grpc_ares_ev_driver_create(&ev_driver, interested_parties);
-  if (err != GRPC_ERROR_NONE) {
-    GRPC_LOG_IF_ERROR("grpc_ares_ev_driver_create() failed", err);
-    goto error_cleanup;
-  }
+  error = grpc_ares_ev_driver_create(&ev_driver, interested_parties);
+  if (error != GRPC_ERROR_NONE) goto error_cleanup;
 
   grpc_ares_request *r = gpr_malloc(sizeof(grpc_ares_request));
   gpr_mu_init(&r->mu);
   r->ev_driver = ev_driver;
   r->on_done = on_done;
-  r->addrs_out = addrs;
-  r->default_port = gpr_strdup(default_port);
-  r->port = port;
-  r->host = host;
+  r->lb_addrs_out = addrs;
   r->success = false;
   r->error = GRPC_ERROR_NONE;
   ares_channel *channel = grpc_ares_ev_driver_get_channel(r->ev_driver);
-  gpr_ref_init(&r->pending_queries, 2);
+
+  // If dns_server is specified, use it.
+  if (dns_server != NULL) {
+    gpr_log(GPR_INFO, "Using DNS server %s", dns_server);
+    grpc_resolved_address addr;
+    if (grpc_parse_ipv4_hostport(dns_server, &addr, false /* log_errors */)) {
+      r->dns_server_addr.family = AF_INET;
+      memcpy(&r->dns_server_addr.addr.addr4, addr.addr, addr.len);
+      r->dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr);
+      r->dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr);
+    } else if (grpc_parse_ipv6_hostport(dns_server, &addr,
+                                        false /* log_errors */)) {
+      r->dns_server_addr.family = AF_INET6;
+      memcpy(&r->dns_server_addr.addr.addr6, addr.addr, addr.len);
+      r->dns_server_addr.tcp_port = grpc_sockaddr_get_port(&addr);
+      r->dns_server_addr.udp_port = grpc_sockaddr_get_port(&addr);
+    } else {
+      error = grpc_error_set_str(
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("cannot parse authority"),
+          GRPC_ERROR_STR_TARGET_ADDRESS, grpc_slice_from_copied_string(name));
+      gpr_free(r);
+      goto error_cleanup;
+    }
+    int status = ares_set_servers_ports(*channel, &r->dns_server_addr);
+    if (status != ARES_SUCCESS) {
+      char *error_msg;
+      gpr_asprintf(&error_msg, "C-ares status is not ARES_SUCCESS: %s",
+                   ares_strerror(status));
+      error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_msg);
+      gpr_free(error_msg);
+      gpr_free(r);
+      goto error_cleanup;
+    }
+  }
+  // An extra reference is put here to avoid destroying the request in
+  // on_done_cb before calling grpc_ares_ev_driver_start.
+  gpr_ref_init(&r->pending_queries, 1);
   if (grpc_ipv6_loopback_available()) {
-    gpr_ref(&r->pending_queries);
-    ares_gethostbyname(*channel, r->host, AF_INET6, on_done_cb, r);
+    grpc_ares_hostbyname_request *hr = create_hostbyname_request(
+        r, host, strhtons(port), false /* is_balancer */);
+    ares_gethostbyname(*channel, hr->host, AF_INET6, on_hostbyname_done_cb, hr);
+  }
+  grpc_ares_hostbyname_request *hr = create_hostbyname_request(
+      r, host, strhtons(port), false /* is_balancer */);
+  ares_gethostbyname(*channel, hr->host, AF_INET, on_hostbyname_done_cb, hr);
+  if (check_grpclb) {
+    /* Query the SRV record */
+    grpc_ares_request_ref(r);
+    char *service_name;
+    gpr_asprintf(&service_name, "_grpclb._tcp.%s", host);
+    ares_query(*channel, service_name, ns_c_in, ns_t_srv, on_srv_query_done_cb,
+               r);
+    gpr_free(service_name);
   }
-  ares_gethostbyname(*channel, r->host, AF_INET, on_done_cb, r);
   /* TODO(zyc): Handle CNAME records here. */
   grpc_ares_ev_driver_start(exec_ctx, r->ev_driver);
   grpc_ares_request_unref(exec_ctx, r);
-  return;
+  gpr_free(host);
+  gpr_free(port);
+  return r;
 
 error_cleanup:
+  GRPC_CLOSURE_SCHED(exec_ctx, on_done, error);
   gpr_free(host);
   gpr_free(port);
+  return NULL;
 }
 
-void (*grpc_resolve_address_ares)(
-    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
-    grpc_pollset_set *interested_parties, grpc_closure *on_done,
-    grpc_resolved_addresses **addrs) = grpc_resolve_address_ares_impl;
+grpc_ares_request *(*grpc_dns_lookup_ares)(
+    grpc_exec_ctx *exec_ctx, const char *dns_server, const char *name,
+    const char *default_port, grpc_pollset_set *interested_parties,
+    grpc_closure *on_done, grpc_lb_addresses **addrs,
+    bool check_grpclb) = grpc_dns_lookup_ares_impl;
+
+void grpc_cancel_ares_request(grpc_exec_ctx *exec_ctx, grpc_ares_request *r) {
+  if (grpc_dns_lookup_ares == grpc_dns_lookup_ares_impl) {
+    grpc_ares_ev_driver_shutdown(exec_ctx, r->ev_driver);
+  }
+}
 
 grpc_error *grpc_ares_init(void) {
   gpr_once_init(&g_basic_init, do_basic_init);
@@ -286,4 +411,66 @@ void grpc_ares_cleanup(void) {
   gpr_mu_unlock(&g_init_mu);
 }
 
+/*
+ * grpc_resolve_address_ares related structs and functions
+ */
+
+typedef struct grpc_resolve_address_ares_request {
+  /** the pointer to receive the resolved addresses */
+  grpc_resolved_addresses **addrs_out;
+  /** currently resolving lb addresses */
+  grpc_lb_addresses *lb_addrs;
+  /** closure to call when the resolve_address_ares request completes */
+  grpc_closure *on_resolve_address_done;
+  /** a closure wrapping on_dns_lookup_done_cb, which should be invoked when the
+      grpc_dns_lookup_ares operation is done. */
+  grpc_closure on_dns_lookup_done;
+} grpc_resolve_address_ares_request;
+
+static void on_dns_lookup_done_cb(grpc_exec_ctx *exec_ctx, void *arg,
+                                  grpc_error *error) {
+  grpc_resolve_address_ares_request *r =
+      (grpc_resolve_address_ares_request *)arg;
+  grpc_resolved_addresses **resolved_addresses = r->addrs_out;
+  if (r->lb_addrs == NULL || r->lb_addrs->num_addresses == 0) {
+    *resolved_addresses = NULL;
+  } else {
+    *resolved_addresses = gpr_zalloc(sizeof(grpc_resolved_addresses));
+    (*resolved_addresses)->naddrs = r->lb_addrs->num_addresses;
+    (*resolved_addresses)->addrs = gpr_zalloc(sizeof(grpc_resolved_address) *
+                                              (*resolved_addresses)->naddrs);
+    for (size_t i = 0; i < (*resolved_addresses)->naddrs; i++) {
+      GPR_ASSERT(!r->lb_addrs->addresses[i].is_balancer);
+      memcpy(&(*resolved_addresses)->addrs[i],
+             &r->lb_addrs->addresses[i].address, sizeof(grpc_resolved_address));
+    }
+  }
+  GRPC_CLOSURE_SCHED(exec_ctx, r->on_resolve_address_done,
+                     GRPC_ERROR_REF(error));
+  grpc_lb_addresses_destroy(exec_ctx, r->lb_addrs);
+  gpr_free(r);
+}
+
+static void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx,
+                                           const char *name,
+                                           const char *default_port,
+                                           grpc_pollset_set *interested_parties,
+                                           grpc_closure *on_done,
+                                           grpc_resolved_addresses **addrs) {
+  grpc_resolve_address_ares_request *r =
+      gpr_zalloc(sizeof(grpc_resolve_address_ares_request));
+  r->addrs_out = addrs;
+  r->on_resolve_address_done = on_done;
+  GRPC_CLOSURE_INIT(&r->on_dns_lookup_done, on_dns_lookup_done_cb, r,
+                    grpc_schedule_on_exec_ctx);
+  grpc_dns_lookup_ares(exec_ctx, NULL /* dns_server */, name, default_port,
+                       interested_parties, &r->on_dns_lookup_done, &r->lb_addrs,
+                       false /* check_grpclb */);
+}
+
+void (*grpc_resolve_address_ares)(
+    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
+    grpc_pollset_set *interested_parties, grpc_closure *on_done,
+    grpc_resolved_addresses **addrs) = grpc_resolve_address_ares_impl;
+
 #endif /* GRPC_ARES == 1 && !defined(GRPC_UV) */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
index 3dd40ea268..5d2d6c993b 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
@@ -1,44 +1,32 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H
 
+#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
+typedef struct grpc_ares_request grpc_ares_request;
+
 /* Asynchronously resolve addr. Use \a default_port if a port isn't designated
    in addr, otherwise use the port in addr. grpc_ares_init() must be called at
    least once before this function. \a on_done may be called directly in this
@@ -51,6 +39,22 @@ extern void (*grpc_resolve_address_ares)(grpc_exec_ctx *exec_ctx,
                                          grpc_closure *on_done,
                                          grpc_resolved_addresses **addresses);
 
+/* Asynchronously resolve addr. It will try to resolve grpclb SRV records in
+  addition to the normal address records. For normal address records, it uses
+  \a default_port if a port isn't designated in \a addr, otherwise it uses the
+  port in \a addr. grpc_ares_init() must be called at least once before this
+  function. \a on_done may be called directly in this function without being
+  scheduled with \a exec_ctx, it must not try to acquire locks that are being
+  held by the caller. */
+extern grpc_ares_request *(*grpc_dns_lookup_ares)(
+    grpc_exec_ctx *exec_ctx, const char *dns_server, const char *addr,
+    const char *default_port, grpc_pollset_set *interested_parties,
+    grpc_closure *on_done, grpc_lb_addresses **addresses, bool check_grpclb);
+
+/* Cancel the pending grpc_ares_request \a request */
+void grpc_cancel_ares_request(grpc_exec_ctx *exec_ctx,
+                              grpc_ares_request *request);
+
 /* Initialize gRPC ares wrapper. Must be called at least once before
    grpc_resolve_address_ares(). */
 grpc_error *grpc_ares_init(void);
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.c
new file mode 100644
index 0000000000..b67636a3e4
--- /dev/null
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.c
@@ -0,0 +1,59 @@
+/*
+ *
+ * Copyright 2016-2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+#if GRPC_ARES != 1 || defined(GRPC_UV)
+
+#include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+
+struct grpc_ares_request {
+  char val;
+};
+
+static grpc_ares_request *grpc_dns_lookup_ares_impl(
+    grpc_exec_ctx *exec_ctx, const char *dns_server, const char *name,
+    const char *default_port, grpc_pollset_set *interested_parties,
+    grpc_closure *on_done, grpc_lb_addresses **addrs, bool check_grpclb) {
+  return NULL;
+}
+
+grpc_ares_request *(*grpc_dns_lookup_ares)(
+    grpc_exec_ctx *exec_ctx, const char *dns_server, const char *name,
+    const char *default_port, grpc_pollset_set *interested_parties,
+    grpc_closure *on_done, grpc_lb_addresses **addrs,
+    bool check_grpclb) = grpc_dns_lookup_ares_impl;
+
+void grpc_cancel_ares_request(grpc_exec_ctx *exec_ctx, grpc_ares_request *r) {}
+
+grpc_error *grpc_ares_init(void) { return GRPC_ERROR_NONE; }
+
+void grpc_ares_cleanup(void) {}
+
+static void grpc_resolve_address_ares_impl(grpc_exec_ctx *exec_ctx,
+                                           const char *name,
+                                           const char *default_port,
+                                           grpc_pollset_set *interested_parties,
+                                           grpc_closure *on_done,
+                                           grpc_resolved_addresses **addrs) {}
+
+void (*grpc_resolve_address_ares)(
+    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
+    grpc_pollset_set *interested_parties, grpc_closure *on_done,
+    grpc_resolved_addresses **addrs) = grpc_resolve_address_ares_impl;
+
+#endif /* GRPC_ARES != 1 || defined(GRPC_UV) */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.c b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.c
index ebe6a07215..5ea75f0554 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -114,7 +99,7 @@ static void dns_shutdown_locked(grpc_exec_ctx *exec_ctx,
   }
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
-    grpc_closure_sched(
+    GRPC_CLOSURE_SCHED(
         exec_ctx, r->next_completion,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
     r->next_completion = NULL;
@@ -147,7 +132,7 @@ static void dns_next_locked(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
 
 static void dns_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                       grpc_error *error) {
-  dns_resolver *r = arg;
+  dns_resolver *r = (dns_resolver *)arg;
 
   r->have_retry_timer = false;
   if (error == GRPC_ERROR_NONE) {
@@ -161,7 +146,7 @@ static void dns_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
 
 static void dns_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                    grpc_error *error) {
-  dns_resolver *r = arg;
+  dns_resolver *r = (dns_resolver *)arg;
   grpc_channel_args *result = NULL;
   GPR_ASSERT(r->resolving);
   r->resolving = false;
@@ -193,8 +178,8 @@ static void dns_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
     } else {
       gpr_log(GPR_DEBUG, "retrying immediately");
     }
-    grpc_closure_init(&r->on_retry, dns_on_retry_timer_locked, r,
-                      grpc_combiner_scheduler(r->base.combiner, false));
+    GRPC_CLOSURE_INIT(&r->on_retry, dns_on_retry_timer_locked, r,
+                      grpc_combiner_scheduler(r->base.combiner));
     grpc_timer_init(exec_ctx, &r->retry_timer, next_try, &r->on_retry, now);
   }
   if (r->resolved_result != NULL) {
@@ -215,8 +200,8 @@ static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx,
   r->addresses = NULL;
   grpc_resolve_address(
       exec_ctx, r->name_to_resolve, r->default_port, r->interested_parties,
-      grpc_closure_create(dns_on_resolved_locked, r,
-                          grpc_combiner_scheduler(r->base.combiner, false)),
+      GRPC_CLOSURE_CREATE(dns_on_resolved_locked, r,
+                          grpc_combiner_scheduler(r->base.combiner)),
       &r->addresses);
 }
 
@@ -227,7 +212,7 @@ static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
     *r->target_result = r->resolved_result == NULL
                             ? NULL
                             : grpc_channel_args_copy(r->resolved_result);
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
     r->published_version = r->resolved_version;
   }
@@ -256,7 +241,7 @@ static grpc_resolver *dns_create(grpc_exec_ctx *exec_ctx,
   char *path = args->uri->path;
   if (path[0] == '/') ++path;
   // Create resolver.
-  dns_resolver *r = gpr_zalloc(sizeof(dns_resolver));
+  dns_resolver *r = (dns_resolver *)gpr_zalloc(sizeof(dns_resolver));
   grpc_resolver_init(&r->base, &dns_resolver_vtable, args->combiner);
   r->name_to_resolve = gpr_strdup(path);
   r->default_port = gpr_strdup(default_port);
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c
new file mode 100644
index 0000000000..56ed4371a9
--- /dev/null
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c
@@ -0,0 +1,254 @@
+//
+// Copyright 2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+// This is similar to the sockaddr resolver, except that it supports a
+// bunch of query args that are useful for dependency injection in tests.
+
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/host_port.h>
+#include <grpc/support/port_platform.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/parse_address.h"
+#include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/combiner.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/unix_sockets_posix.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/support/string.h"
+
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+
+//
+// fake_resolver
+//
+
+typedef struct {
+  // base class -- must be first
+  grpc_resolver base;
+
+  // passed-in parameters
+  grpc_channel_args* channel_args;
+
+  // If not NULL, the next set of resolution results to be returned to
+  // grpc_resolver_next_locked()'s closure.
+  grpc_channel_args* next_results;
+
+  // Results to use for the pretended re-resolution in
+  // fake_resolver_channel_saw_error_locked().
+  grpc_channel_args* results_upon_error;
+
+  // pending next completion, or NULL
+  grpc_closure* next_completion;
+  // target result address for next completion
+  grpc_channel_args** target_result;
+} fake_resolver;
+
+static void fake_resolver_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
+  fake_resolver* r = (fake_resolver*)gr;
+  grpc_channel_args_destroy(exec_ctx, r->next_results);
+  grpc_channel_args_destroy(exec_ctx, r->results_upon_error);
+  grpc_channel_args_destroy(exec_ctx, r->channel_args);
+  gpr_free(r);
+}
+
+static void fake_resolver_shutdown_locked(grpc_exec_ctx* exec_ctx,
+                                          grpc_resolver* resolver) {
+  fake_resolver* r = (fake_resolver*)resolver;
+  if (r->next_completion != NULL) {
+    *r->target_result = NULL;
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, r->next_completion,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
+    r->next_completion = NULL;
+  }
+}
+
+static void fake_resolver_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
+                                                   fake_resolver* r) {
+  if (r->next_completion != NULL && r->next_results != NULL) {
+    *r->target_result =
+        grpc_channel_args_union(r->next_results, r->channel_args);
+    grpc_channel_args_destroy(exec_ctx, r->next_results);
+    r->next_results = NULL;
+    GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
+    r->next_completion = NULL;
+  }
+}
+
+static void fake_resolver_channel_saw_error_locked(grpc_exec_ctx* exec_ctx,
+                                                   grpc_resolver* resolver) {
+  fake_resolver* r = (fake_resolver*)resolver;
+  if (r->next_results == NULL && r->results_upon_error != NULL) {
+    // Pretend we re-resolved.
+    r->next_results = grpc_channel_args_copy(r->results_upon_error);
+  }
+  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
+}
+
+static void fake_resolver_next_locked(grpc_exec_ctx* exec_ctx,
+                                      grpc_resolver* resolver,
+                                      grpc_channel_args** target_result,
+                                      grpc_closure* on_complete) {
+  fake_resolver* r = (fake_resolver*)resolver;
+  GPR_ASSERT(!r->next_completion);
+  r->next_completion = on_complete;
+  r->target_result = target_result;
+  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
+}
+
+static const grpc_resolver_vtable fake_resolver_vtable = {
+    fake_resolver_destroy, fake_resolver_shutdown_locked,
+    fake_resolver_channel_saw_error_locked, fake_resolver_next_locked};
+
+struct grpc_fake_resolver_response_generator {
+  fake_resolver* resolver;  // Set by the fake_resolver constructor to itself.
+  grpc_channel_args* next_response;
+  gpr_refcount refcount;
+};
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_create() {
+  grpc_fake_resolver_response_generator* generator =
+      (grpc_fake_resolver_response_generator*)gpr_zalloc(sizeof(*generator));
+  gpr_ref_init(&generator->refcount, 1);
+  return generator;
+}
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_ref(
+    grpc_fake_resolver_response_generator* generator) {
+  gpr_ref(&generator->refcount);
+  return generator;
+}
+
+void grpc_fake_resolver_response_generator_unref(
+    grpc_fake_resolver_response_generator* generator) {
+  if (gpr_unref(&generator->refcount)) {
+    gpr_free(generator);
+  }
+}
+
+static void set_response_cb(grpc_exec_ctx* exec_ctx, void* arg,
+                            grpc_error* error) {
+  grpc_fake_resolver_response_generator* generator =
+      (grpc_fake_resolver_response_generator*)arg;
+  fake_resolver* r = generator->resolver;
+  if (r->next_results != NULL) {
+    grpc_channel_args_destroy(exec_ctx, r->next_results);
+  }
+  r->next_results = generator->next_response;
+  if (r->results_upon_error != NULL) {
+    grpc_channel_args_destroy(exec_ctx, r->results_upon_error);
+  }
+  r->results_upon_error = grpc_channel_args_copy(generator->next_response);
+  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
+}
+
+void grpc_fake_resolver_response_generator_set_response(
+    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
+    grpc_channel_args* next_response) {
+  GPR_ASSERT(generator->resolver != NULL);
+  generator->next_response = grpc_channel_args_copy(next_response);
+  GRPC_CLOSURE_SCHED(
+      exec_ctx, GRPC_CLOSURE_CREATE(set_response_cb, generator,
+                                    grpc_combiner_scheduler(
+                                        generator->resolver->base.combiner)),
+      GRPC_ERROR_NONE);
+}
+
+static void* response_generator_arg_copy(void* p) {
+  return grpc_fake_resolver_response_generator_ref(
+      (grpc_fake_resolver_response_generator*)p);
+}
+
+static void response_generator_arg_destroy(grpc_exec_ctx* exec_ctx, void* p) {
+  grpc_fake_resolver_response_generator_unref(
+      (grpc_fake_resolver_response_generator*)p);
+}
+
+static int response_generator_cmp(void* a, void* b) { return GPR_ICMP(a, b); }
+
+static const grpc_arg_pointer_vtable response_generator_arg_vtable = {
+    response_generator_arg_copy, response_generator_arg_destroy,
+    response_generator_cmp};
+
+grpc_arg grpc_fake_resolver_response_generator_arg(
+    grpc_fake_resolver_response_generator* generator) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR;
+  arg.value.pointer.p = generator;
+  arg.value.pointer.vtable = &response_generator_arg_vtable;
+  return arg;
+}
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_get_response_generator(const grpc_channel_args* args) {
+  const grpc_arg* arg =
+      grpc_channel_args_find(args, GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR);
+  if (arg == NULL || arg->type != GRPC_ARG_POINTER) return NULL;
+  return (grpc_fake_resolver_response_generator*)arg->value.pointer.p;
+}
+
+//
+// fake_resolver_factory
+//
+
+static void fake_resolver_factory_ref(grpc_resolver_factory* factory) {}
+
+static void fake_resolver_factory_unref(grpc_resolver_factory* factory) {}
+
+static grpc_resolver* fake_resolver_create(grpc_exec_ctx* exec_ctx,
+                                           grpc_resolver_factory* factory,
+                                           grpc_resolver_args* args) {
+  fake_resolver* r = (fake_resolver*)gpr_zalloc(sizeof(*r));
+  r->channel_args = grpc_channel_args_copy(args->args);
+  grpc_resolver_init(&r->base, &fake_resolver_vtable, args->combiner);
+  grpc_fake_resolver_response_generator* response_generator =
+      grpc_fake_resolver_get_response_generator(args->args);
+  if (response_generator != NULL) response_generator->resolver = r;
+  return &r->base;
+}
+
+static char* fake_resolver_get_default_authority(grpc_resolver_factory* factory,
+                                                 grpc_uri* uri) {
+  const char* path = uri->path;
+  if (path[0] == '/') ++path;
+  return gpr_strdup(path);
+}
+
+static const grpc_resolver_factory_vtable fake_resolver_factory_vtable = {
+    fake_resolver_factory_ref, fake_resolver_factory_unref,
+    fake_resolver_create, fake_resolver_get_default_authority, "fake"};
+
+static grpc_resolver_factory fake_resolver_factory = {
+    &fake_resolver_factory_vtable};
+
+void grpc_resolver_fake_init(void) {
+  grpc_register_resolver_type(&fake_resolver_factory);
+}
+
+void grpc_resolver_fake_shutdown(void) {}
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h
new file mode 100644
index 0000000000..c084ef2a58
--- /dev/null
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h
@@ -0,0 +1,60 @@
+//
+// Copyright 2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H
+#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H
+
+#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
+#include "src/core/ext/filters/client_channel/uri_parser.h"
+#include "src/core/lib/channel/channel_args.h"
+
+#define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \
+  "grpc.fake_resolver.response_generator"
+
+void grpc_resolver_fake_init();
+
+// Instances of \a grpc_fake_resolver_response_generator are passed to the
+// fake resolver in a channel argument (see \a
+// grpc_fake_resolver_response_generator_arg) in order to inject and trigger
+// custom resolutions. See also \a
+// grpc_fake_resolver_response_generator_set_response.
+typedef struct grpc_fake_resolver_response_generator
+    grpc_fake_resolver_response_generator;
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_create();
+
+// Instruct the fake resolver associated with the \a response_generator instance
+// to trigger a new resolution for \a uri and \a args.
+void grpc_fake_resolver_response_generator_set_response(
+    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
+    grpc_channel_args* next_response);
+
+// Return a \a grpc_arg for a \a grpc_fake_resolver_response_generator instance.
+grpc_arg grpc_fake_resolver_response_generator_arg(
+    grpc_fake_resolver_response_generator* generator);
+// Return the \a grpc_fake_resolver_response_generator instance in \a args or
+// NULL.
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_get_response_generator(const grpc_channel_args* args);
+
+grpc_fake_resolver_response_generator*
+grpc_fake_resolver_response_generator_ref(
+    grpc_fake_resolver_response_generator* generator);
+void grpc_fake_resolver_response_generator_unref(
+    grpc_fake_resolver_response_generator* generator);
+
+#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H \
+          */
diff --git a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.c b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.c
index 4d7d878c23..7ceb8f40a1 100644
--- a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.c
+++ b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015-2016, Google Inc.
- * All rights reserved.
+ * Copyright 2015-2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -88,7 +73,9 @@ static void sockaddr_shutdown_locked(grpc_exec_ctx *exec_ctx,
   sockaddr_resolver *r = (sockaddr_resolver *)resolver;
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, r->next_completion,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resolver Shutdown"));
     r->next_completion = NULL;
   }
 }
@@ -118,7 +105,7 @@ static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
     grpc_arg arg = grpc_lb_addresses_create_channel_arg(r->addresses);
     *r->target_result =
         grpc_channel_args_copy_and_add(r->channel_args, &arg, 1);
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
   }
 }
@@ -190,7 +177,8 @@ static grpc_resolver *sockaddr_create(grpc_exec_ctx *exec_ctx,
     return NULL;
   }
   /* Instantiate resolver. */
-  sockaddr_resolver *r = gpr_zalloc(sizeof(sockaddr_resolver));
+  sockaddr_resolver *r =
+      (sockaddr_resolver *)gpr_zalloc(sizeof(sockaddr_resolver));
   r->addresses = addresses;
   r->channel_args = grpc_channel_args_copy(args->args);
   grpc_resolver_init(&r->base, &sockaddr_resolver_vtable, args->combiner);
diff --git a/src/core/ext/filters/client_channel/resolver_factory.c b/src/core/ext/filters/client_channel/resolver_factory.c
index 07f9e4cf03..6f0a7c1e36 100644
--- a/src/core/ext/filters/client_channel/resolver_factory.c
+++ b/src/core/ext/filters/client_channel/resolver_factory.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/resolver_factory.h b/src/core/ext/filters/client_channel/resolver_factory.h
index f2fcfc06fe..6bd7929d4e 100644
--- a/src/core/ext/filters/client_channel/resolver_factory.h
+++ b/src/core/ext/filters/client_channel/resolver_factory.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/resolver_registry.c b/src/core/ext/filters/client_channel/resolver_registry.c
index fa997bd68f..1a0fb0bc3c 100644
--- a/src/core/ext/filters/client_channel/resolver_registry.c
+++ b/src/core/ext/filters/client_channel/resolver_registry.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/resolver_registry.h b/src/core/ext/filters/client_channel/resolver_registry.h
index f2e9f9249c..692490543d 100644
--- a/src/core/ext/filters/client_channel/resolver_registry.h
+++ b/src/core/ext/filters/client_channel/resolver_registry.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/retry_throttle.c b/src/core/ext/filters/client_channel/retry_throttle.c
index dd78a17844..3009e21d49 100644
--- a/src/core/ext/filters/client_channel/retry_throttle.c
+++ b/src/core/ext/filters/client_channel/retry_throttle.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/retry_throttle.h b/src/core/ext/filters/client_channel/retry_throttle.h
index 640865cf90..bf99297e98 100644
--- a/src/core/ext/filters/client_channel/retry_throttle.h
+++ b/src/core/ext/filters/client_channel/retry_throttle.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/subchannel.c b/src/core/ext/filters/client_channel/subchannel.c
index ddc24f7c71..bdaf567d6a 100644
--- a/src/core/ext/filters/client_channel/subchannel.c
+++ b/src/core/ext/filters/client_channel/subchannel.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -155,25 +140,13 @@ struct grpc_subchannel_call {
 static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *subchannel,
                                  grpc_error *error);
 
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+#ifndef NDEBUG
 #define REF_REASON reason
-#define REF_LOG(name, p)                                                  \
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p   ref %d -> %d %s", \
-          (name), (p), (p)->refs.count, (p)->refs.count + 1, reason)
-#define UNREF_LOG(name, p)                                                \
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "%s: %p unref %d -> %d %s", \
-          (name), (p), (p)->refs.count, (p)->refs.count - 1, reason)
 #define REF_MUTATE_EXTRA_ARGS \
   GRPC_SUBCHANNEL_REF_EXTRA_ARGS, const char *purpose
 #define REF_MUTATE_PURPOSE(x) , file, line, reason, x
 #else
 #define REF_REASON ""
-#define REF_LOG(name, p) \
-  do {                   \
-  } while (0)
-#define UNREF_LOG(name, p) \
-  do {                     \
-  } while (0)
 #define REF_MUTATE_EXTRA_ARGS
 #define REF_MUTATE_PURPOSE(x)
 #endif
@@ -215,6 +188,7 @@ static void subchannel_destroy(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_connector_unref(exec_ctx, c->connector);
   grpc_pollset_set_destroy(exec_ctx, c->pollset_set);
   grpc_subchannel_key_destroy(exec_ctx, c->key);
+  gpr_mu_destroy(&c->mu);
   gpr_free(c);
 }
 
@@ -222,10 +196,12 @@ static gpr_atm ref_mutate(grpc_subchannel *c, gpr_atm delta,
                           int barrier REF_MUTATE_EXTRA_ARGS) {
   gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
                             : gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
-  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
-          "SUBCHANNEL: %p %s 0x%08" PRIxPTR " -> 0x%08" PRIxPTR " [%s]", c,
-          purpose, old_val, old_val + delta, reason);
+#ifndef NDEBUG
+  if (GRPC_TRACER_ON(grpc_trace_stream_refcount)) {
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "SUBCHANNEL: %p %12s 0x%" PRIxPTR " -> 0x%" PRIxPTR " [%s]", c,
+            purpose, old_val, old_val + delta, reason);
+  }
 #endif
   return old_val;
 }
@@ -283,6 +259,7 @@ static void disconnect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
 void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
                            grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
   gpr_atm old_refs;
+  // add a weak ref and subtract a strong ref (atomically)
   old_refs = ref_mutate(c, (gpr_atm)1 - (gpr_atm)(1 << INTERNAL_REF_BITS),
                         1 REF_MUTATE_PURPOSE("STRONG_UNREF"));
   if ((old_refs & STRONG_REF_MASK) == (1 << INTERNAL_REF_BITS)) {
@@ -297,7 +274,7 @@ void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
   gpr_atm old_refs;
   old_refs = ref_mutate(c, -(gpr_atm)1, 1 REF_MUTATE_PURPOSE("WEAK_UNREF"));
   if (old_refs == 1) {
-    grpc_closure_sched(exec_ctx, grpc_closure_create(subchannel_destroy, c,
+    GRPC_CLOSURE_SCHED(exec_ctx, GRPC_CLOSURE_CREATE(subchannel_destroy, c,
                                                      grpc_schedule_on_exec_ctx),
                        GRPC_ERROR_NONE);
   }
@@ -306,7 +283,7 @@ void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
 grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
                                         grpc_connector *connector,
                                         const grpc_subchannel_args *args) {
-  grpc_subchannel_key *key = grpc_subchannel_key_create(connector, args);
+  grpc_subchannel_key *key = grpc_subchannel_key_create(args);
   grpc_subchannel *c = grpc_subchannel_index_find(exec_ctx, key);
   if (c) {
     grpc_subchannel_key_destroy(exec_ctx, key);
@@ -347,7 +324,7 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
   if (new_args != NULL) grpc_channel_args_destroy(exec_ctx, new_args);
   c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
       &c->root_external_state_watcher;
-  grpc_closure_init(&c->connected, subchannel_connected, c,
+  GRPC_CLOSURE_INIT(&c->connected, subchannel_connected, c,
                     grpc_schedule_on_exec_ctx);
   grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
                                "subchannel");
@@ -435,7 +412,7 @@ static void on_external_state_watcher_done(grpc_exec_ctx *exec_ctx, void *arg,
   gpr_mu_unlock(&w->subchannel->mu);
   GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, w->subchannel, "external_state_watcher");
   gpr_free(w);
-  grpc_closure_run(exec_ctx, follow_up, GRPC_ERROR_REF(error));
+  GRPC_CLOSURE_RUN(exec_ctx, follow_up, GRPC_ERROR_REF(error));
 }
 
 static void on_alarm(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
@@ -501,7 +478,7 @@ static void maybe_start_connecting_locked(grpc_exec_ctx *exec_ctx,
       gpr_log(GPR_INFO, "Retry in %" PRId64 ".%09d seconds",
               time_til_next.tv_sec, time_til_next.tv_nsec);
     }
-    grpc_closure_init(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx);
+    GRPC_CLOSURE_INIT(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx);
     grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, &c->on_alarm, now);
   }
 }
@@ -527,7 +504,7 @@ void grpc_subchannel_notify_on_state_change(
     w->subchannel = c;
     w->pollset_set = interested_parties;
     w->notify = notify;
-    grpc_closure_init(&w->closure, on_external_state_watcher_done, w,
+    GRPC_CLOSURE_INIT(&w->closure, on_external_state_watcher_done, w,
                       grpc_schedule_on_exec_ctx);
     if (interested_parties != NULL) {
       grpc_pollset_set_add_pollset_set(exec_ctx, c->pollset_set,
@@ -648,14 +625,13 @@ static bool publish_transport_locked(grpc_exec_ctx *exec_ctx,
   sw_subchannel = gpr_malloc(sizeof(*sw_subchannel));
   sw_subchannel->subchannel = c;
   sw_subchannel->connectivity_state = GRPC_CHANNEL_READY;
-  grpc_closure_init(&sw_subchannel->closure, subchannel_on_child_state_changed,
+  GRPC_CLOSURE_INIT(&sw_subchannel->closure, subchannel_on_child_state_changed,
                     sw_subchannel, grpc_schedule_on_exec_ctx);
 
   if (c->disconnected) {
     gpr_free(sw_subchannel);
     grpc_channel_stack_destroy(exec_ctx, stk);
     gpr_free(con);
-    GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
     return false;
   }
 
@@ -769,6 +745,11 @@ grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
   return GET_CONNECTED_SUBCHANNEL(c, acq);
 }
 
+const grpc_subchannel_key *grpc_subchannel_get_key(
+    const grpc_subchannel *subchannel) {
+  return subchannel->key;
+}
+
 grpc_error *grpc_connected_subchannel_create_call(
     grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
     const grpc_connected_subchannel_call_args *args,
@@ -828,10 +809,7 @@ const char *grpc_get_subchannel_address_uri_arg(const grpc_channel_args *args) {
 }
 
 grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address *addr) {
-  grpc_arg new_arg;
-  new_arg.key = GRPC_ARG_SUBCHANNEL_ADDRESS;
-  new_arg.type = GRPC_ARG_STRING;
-  new_arg.value.string =
-      addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup("");
-  return new_arg;
+  return grpc_channel_arg_string_create(
+      GRPC_ARG_SUBCHANNEL_ADDRESS,
+      addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup(""));
 }
diff --git a/src/core/ext/filters/client_channel/subchannel.h b/src/core/ext/filters/client_channel/subchannel.h
index e433c33e40..6d2abb04df 100644
--- a/src/core/ext/filters/client_channel/subchannel.h
+++ b/src/core/ext/filters/client_channel/subchannel.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -50,8 +35,9 @@ typedef struct grpc_subchannel grpc_subchannel;
 typedef struct grpc_connected_subchannel grpc_connected_subchannel;
 typedef struct grpc_subchannel_call grpc_subchannel_call;
 typedef struct grpc_subchannel_args grpc_subchannel_args;
+typedef struct grpc_subchannel_key grpc_subchannel_key;
 
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+#ifndef NDEBUG
 #define GRPC_SUBCHANNEL_REF(p, r) \
   grpc_subchannel_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_REF_FROM_WEAK_REF(p, r) \
@@ -155,6 +141,10 @@ void grpc_connected_subchannel_ping(grpc_exec_ctx *exec_ctx,
 grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
     grpc_subchannel *subchannel);
 
+/** return the subchannel index key for \a subchannel */
+const grpc_subchannel_key *grpc_subchannel_get_key(
+    const grpc_subchannel *subchannel);
+
 /** continue processing a transport op */
 void grpc_subchannel_call_process_op(grpc_exec_ctx *exec_ctx,
                                      grpc_subchannel_call *subchannel_call,
diff --git a/src/core/ext/filters/client_channel/subchannel_index.c b/src/core/ext/filters/client_channel/subchannel_index.c
index f6ef4a845e..a33ab950bf 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.c
+++ b/src/core/ext/filters/client_channel/subchannel_index.c
@@ -1,33 +1,18 @@
 //
 //
-// Copyright 2016, Google Inc.
-// All rights reserved.
+// Copyright 2016 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 //
 
@@ -50,12 +35,13 @@ static gpr_avl g_subchannel_index;
 static gpr_mu g_mu;
 
 struct grpc_subchannel_key {
-  grpc_connector *connector;
   grpc_subchannel_args args;
 };
 
 GPR_TLS_DECL(subchannel_index_exec_ctx);
 
+static bool g_force_creation = false;
+
 static void enter_ctx(grpc_exec_ctx *exec_ctx) {
   GPR_ASSERT(gpr_tls_get(&subchannel_index_exec_ctx) == 0);
   gpr_tls_set(&subchannel_index_exec_ctx, (intptr_t)exec_ctx);
@@ -73,10 +59,9 @@ static grpc_exec_ctx *current_ctx() {
 }
 
 static grpc_subchannel_key *create_key(
-    grpc_connector *connector, const grpc_subchannel_args *args,
+    const grpc_subchannel_args *args,
     grpc_channel_args *(*copy_channel_args)(const grpc_channel_args *args)) {
   grpc_subchannel_key *k = gpr_malloc(sizeof(*k));
-  k->connector = grpc_connector_ref(connector);
   k->args.filter_count = args->filter_count;
   if (k->args.filter_count > 0) {
     k->args.filters =
@@ -91,19 +76,18 @@ static grpc_subchannel_key *create_key(
 }
 
 grpc_subchannel_key *grpc_subchannel_key_create(
-    grpc_connector *connector, const grpc_subchannel_args *args) {
-  return create_key(connector, args, grpc_channel_args_normalize);
+    const grpc_subchannel_args *args) {
+  return create_key(args, grpc_channel_args_normalize);
 }
 
 static grpc_subchannel_key *subchannel_key_copy(grpc_subchannel_key *k) {
-  return create_key(k->connector, &k->args, grpc_channel_args_copy);
+  return create_key(&k->args, grpc_channel_args_copy);
 }
 
-static int subchannel_key_compare(grpc_subchannel_key *a,
-                                  grpc_subchannel_key *b) {
-  int c = GPR_ICMP(a->connector, b->connector);
-  if (c != 0) return c;
-  c = GPR_ICMP(a->args.filter_count, b->args.filter_count);
+int grpc_subchannel_key_compare(const grpc_subchannel_key *a,
+                                const grpc_subchannel_key *b) {
+  if (g_force_creation) return false;
+  int c = GPR_ICMP(a->args.filter_count, b->args.filter_count);
   if (c != 0) return c;
   if (a->args.filter_count > 0) {
     c = memcmp(a->args.filters, b->args.filters,
@@ -115,7 +99,6 @@ static int subchannel_key_compare(grpc_subchannel_key *a,
 
 void grpc_subchannel_key_destroy(grpc_exec_ctx *exec_ctx,
                                  grpc_subchannel_key *k) {
-  grpc_connector_unref(exec_ctx, k->connector);
   gpr_free((grpc_channel_args *)k->args.filters);
   grpc_channel_args_destroy(exec_ctx, (grpc_channel_args *)k->args.args);
   gpr_free(k);
@@ -128,7 +111,7 @@ static void sck_avl_destroy(void *p) {
 static void *sck_avl_copy(void *p) { return subchannel_key_copy(p); }
 
 static long sck_avl_compare(void *a, void *b) {
-  return subchannel_key_compare(a, b);
+  return grpc_subchannel_key_compare(a, b);
 }
 
 static void scv_avl_destroy(void *p) {
@@ -183,8 +166,11 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
   enter_ctx(exec_ctx);
 
   grpc_subchannel *c = NULL;
+  bool need_to_unref_constructed;
 
   while (c == NULL) {
+    need_to_unref_constructed = false;
+
     // Compare and swap loop:
     // - take a reference to the current index
     gpr_mu_lock(&g_mu);
@@ -194,8 +180,11 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
     // - Check to see if a subchannel already exists
     c = gpr_avl_get(index, key);
     if (c != NULL) {
+      c = GRPC_SUBCHANNEL_REF_FROM_WEAK_REF(c, "index_register");
+    }
+    if (c != NULL) {
       // yes -> we're done
-      GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, constructed, "index_register");
+      need_to_unref_constructed = true;
     } else {
       // no -> update the avl and compare/swap
       gpr_avl updated =
@@ -219,6 +208,10 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
 
   leave_ctx(exec_ctx);
 
+  if (need_to_unref_constructed) {
+    GRPC_SUBCHANNEL_UNREF(exec_ctx, constructed, "index_register");
+  }
+
   return c;
 }
 
@@ -260,3 +253,7 @@ void grpc_subchannel_index_unregister(grpc_exec_ctx *exec_ctx,
 
   leave_ctx(exec_ctx);
 }
+
+void grpc_subchannel_index_test_only_set_force_creation(bool force_creation) {
+  g_force_creation = force_creation;
+}
diff --git a/src/core/ext/filters/client_channel/subchannel_index.h b/src/core/ext/filters/client_channel/subchannel_index.h
index f673ade378..98d882a453 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.h
+++ b/src/core/ext/filters/client_channel/subchannel_index.h
@@ -1,50 +1,32 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INDEX_H
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INDEX_H
 
-#include "src/core/ext/filters/client_channel/connector.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
 
 /** \file Provides an index of active subchannels so that they can be
     shared amongst channels */
 
-typedef struct grpc_subchannel_key grpc_subchannel_key;
-
 /** Create a key that can be used to uniquely identify a subchannel */
 grpc_subchannel_key *grpc_subchannel_key_create(
-    grpc_connector *con, const grpc_subchannel_args *args);
+    const grpc_subchannel_args *args);
 
 /** Destroy a subchannel key */
 void grpc_subchannel_key_destroy(grpc_exec_ctx *exec_ctx,
@@ -69,9 +51,24 @@ void grpc_subchannel_index_unregister(grpc_exec_ctx *exec_ctx,
                                       grpc_subchannel_key *key,
                                       grpc_subchannel *constructed);
 
+int grpc_subchannel_key_compare(const grpc_subchannel_key *a,
+                                const grpc_subchannel_key *b);
+
 /** Initialize the subchannel index (global) */
 void grpc_subchannel_index_init(void);
 /** Shutdown the subchannel index (global) */
 void grpc_subchannel_index_shutdown(void);
 
+/** \em TEST ONLY.
+ * If \a force_creation is true, all key comparisons will be false, resulting in
+ * new subchannels always being created. Otherwise, the keys will be compared as
+ * usual.
+ *
+ * This function is *not* threadsafe on purpose: it should *only* be used in
+ * test code.
+ *
+ * Tests using this function \em MUST run tests with and without \a
+ * force_creation set. */
+void grpc_subchannel_index_test_only_set_force_creation(bool force_creation);
+
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INDEX_H */
diff --git a/src/core/ext/filters/client_channel/uri_parser.c b/src/core/ext/filters/client_channel/uri_parser.c
index b233d835cb..e841928760 100644
--- a/src/core/ext/filters/client_channel/uri_parser.c
+++ b/src/core/ext/filters/client_channel/uri_parser.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/client_channel/uri_parser.h b/src/core/ext/filters/client_channel/uri_parser.h
index b889040b16..05ca2e00e4 100644
--- a/src/core/ext/filters/client_channel/uri_parser.h
+++ b/src/core/ext/filters/client_channel/uri_parser.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/deadline/deadline_filter.c b/src/core/ext/filters/deadline/deadline_filter.c
index 2e03d16bf6..6789903c95 100644
--- a/src/core/ext/filters/deadline/deadline_filter.c
+++ b/src/core/ext/filters/deadline/deadline_filter.c
@@ -1,32 +1,17 @@
 //
-// Copyright 2016, Google Inc.
-// All rights reserved.
+// Copyright 2016 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 
 #include "src/core/ext/filters/deadline/deadline_filter.h"
@@ -52,8 +37,8 @@
 // Timer callback.
 static void timer_callback(grpc_exec_ctx* exec_ctx, void* arg,
                            grpc_error* error) {
-  grpc_call_element* elem = arg;
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_call_element* elem = (grpc_call_element*)arg;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   if (error != GRPC_ERROR_CANCELLED) {
     grpc_call_element_signal_error(
         exec_ctx, elem,
@@ -72,7 +57,7 @@ static void start_timer_if_needed(grpc_exec_ctx* exec_ctx,
   if (gpr_time_cmp(deadline, gpr_inf_future(GPR_CLOCK_MONOTONIC)) == 0) {
     return;
   }
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   grpc_deadline_timer_state cur_state;
   grpc_closure* closure = NULL;
 retry:
@@ -89,7 +74,7 @@ retry:
         // If we've already created and destroyed a timer, we always create a
         // new closure: we have no other guarantee that the inlined closure is
         // not in use (it may hold a pending call to timer_callback)
-        closure = grpc_closure_create(timer_callback, elem,
+        closure = GRPC_CLOSURE_CREATE(timer_callback, elem,
                                       grpc_schedule_on_exec_ctx);
       } else {
         goto retry;
@@ -100,7 +85,7 @@ retry:
                           GRPC_DEADLINE_STATE_INITIAL,
                           GRPC_DEADLINE_STATE_PENDING)) {
         closure =
-            grpc_closure_init(&deadline_state->timer_callback, timer_callback,
+            GRPC_CLOSURE_INIT(&deadline_state->timer_callback, timer_callback,
                               elem, grpc_schedule_on_exec_ctx);
       } else {
         goto retry;
@@ -127,10 +112,10 @@ static void cancel_timer_if_needed(grpc_exec_ctx* exec_ctx,
 
 // Callback run when the call is complete.
 static void on_complete(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
-  grpc_deadline_state* deadline_state = arg;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)arg;
   cancel_timer_if_needed(exec_ctx, deadline_state);
   // Invoke the next callback.
-  grpc_closure_run(exec_ctx, deadline_state->next_on_complete,
+  GRPC_CLOSURE_RUN(exec_ctx, deadline_state->next_on_complete,
                    GRPC_ERROR_REF(error));
 }
 
@@ -138,7 +123,7 @@ static void on_complete(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
 static void inject_on_complete_cb(grpc_deadline_state* deadline_state,
                                   grpc_transport_stream_op_batch* op) {
   deadline_state->next_on_complete = op->on_complete;
-  grpc_closure_init(&deadline_state->on_complete, on_complete, deadline_state,
+  GRPC_CLOSURE_INIT(&deadline_state->on_complete, on_complete, deadline_state,
                     grpc_schedule_on_exec_ctx);
   op->on_complete = &deadline_state->on_complete;
 }
@@ -160,7 +145,7 @@ static void start_timer_after_init(grpc_exec_ctx* exec_ctx, void* arg,
 void grpc_deadline_state_init(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
                               grpc_call_stack* call_stack,
                               gpr_timespec deadline) {
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   deadline_state->call_stack = call_stack;
   // Deadline will always be infinite on servers, so the timer will only be
   // set on clients with a finite deadline.
@@ -176,21 +161,21 @@ void grpc_deadline_state_init(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     struct start_timer_after_init_state* state = gpr_malloc(sizeof(*state));
     state->elem = elem;
     state->deadline = deadline;
-    grpc_closure_init(&state->closure, start_timer_after_init, state,
+    GRPC_CLOSURE_INIT(&state->closure, start_timer_after_init, state,
                       grpc_schedule_on_exec_ctx);
-    grpc_closure_sched(exec_ctx, &state->closure, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, &state->closure, GRPC_ERROR_NONE);
   }
 }
 
 void grpc_deadline_state_destroy(grpc_exec_ctx* exec_ctx,
                                  grpc_call_element* elem) {
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   cancel_timer_if_needed(exec_ctx, deadline_state);
 }
 
 void grpc_deadline_state_reset(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
                                gpr_timespec new_deadline) {
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   cancel_timer_if_needed(exec_ctx, deadline_state);
   start_timer_if_needed(exec_ctx, elem, new_deadline);
 }
@@ -198,7 +183,7 @@ void grpc_deadline_state_reset(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
 void grpc_deadline_state_client_start_transport_stream_op_batch(
     grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     grpc_transport_stream_op_batch* op) {
-  grpc_deadline_state* deadline_state = elem->call_data;
+  grpc_deadline_state* deadline_state = (grpc_deadline_state*)elem->call_data;
   if (op->cancel_stream) {
     cancel_timer_if_needed(exec_ctx, deadline_state);
   } else {
@@ -271,8 +256,8 @@ static void client_start_transport_stream_op_batch(
 // Callback for receiving initial metadata on the server.
 static void recv_initial_metadata_ready(grpc_exec_ctx* exec_ctx, void* arg,
                                         grpc_error* error) {
-  grpc_call_element* elem = arg;
-  server_call_data* calld = elem->call_data;
+  grpc_call_element* elem = (grpc_call_element*)arg;
+  server_call_data* calld = (server_call_data*)elem->call_data;
   // Get deadline from metadata and start the timer if needed.
   start_timer_if_needed(exec_ctx, elem, calld->recv_initial_metadata->deadline);
   // Invoke the next callback.
@@ -284,7 +269,7 @@ static void recv_initial_metadata_ready(grpc_exec_ctx* exec_ctx, void* arg,
 static void server_start_transport_stream_op_batch(
     grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     grpc_transport_stream_op_batch* op) {
-  server_call_data* calld = elem->call_data;
+  server_call_data* calld = (server_call_data*)elem->call_data;
   if (op->cancel_stream) {
     cancel_timer_if_needed(exec_ctx, &calld->base.deadline_state);
   } else {
@@ -296,7 +281,7 @@ static void server_start_transport_stream_op_batch(
           op->payload->recv_initial_metadata.recv_initial_metadata_ready;
       calld->recv_initial_metadata =
           op->payload->recv_initial_metadata.recv_initial_metadata;
-      grpc_closure_init(&calld->recv_initial_metadata_ready,
+      GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
                         recv_initial_metadata_ready, elem,
                         grpc_schedule_on_exec_ctx);
       op->payload->recv_initial_metadata.recv_initial_metadata_ready =
@@ -356,8 +341,8 @@ static bool maybe_add_deadline_filter(grpc_exec_ctx* exec_ctx,
                                       void* arg) {
   return grpc_deadline_checking_enabled(
              grpc_channel_stack_builder_get_channel_arguments(builder))
-             ? grpc_channel_stack_builder_prepend_filter(builder, arg, NULL,
-                                                         NULL)
+             ? grpc_channel_stack_builder_prepend_filter(
+                   builder, (const grpc_channel_filter*)arg, NULL, NULL)
              : true;
 }
 
diff --git a/src/core/ext/filters/deadline/deadline_filter.h b/src/core/ext/filters/deadline/deadline_filter.h
index 5050453fa1..420bf7065a 100644
--- a/src/core/ext/filters/deadline/deadline_filter.h
+++ b/src/core/ext/filters/deadline/deadline_filter.h
@@ -1,32 +1,17 @@
 //
-// Copyright 2016, Google Inc.
-// All rights reserved.
+// Copyright 2016 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 
 #ifndef GRPC_CORE_EXT_FILTERS_DEADLINE_DEADLINE_FILTER_H
diff --git a/src/core/ext/filters/http/client/http_client_filter.c b/src/core/ext/filters/http/client/http_client_filter.c
index d8ae080eee..90f0aed7a0 100644
--- a/src/core/ext/filters/http/client/http_client_filter.c
+++ b/src/core/ext/filters/http/client/http_client_filter.c
@@ -1,32 +1,17 @@
 /*
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -173,7 +158,7 @@ static void hc_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx,
   } else {
     GRPC_ERROR_REF(error);
   }
-  grpc_closure_run(exec_ctx, calld->on_done_recv_initial_metadata, error);
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_done_recv_initial_metadata, error);
 }
 
 static void hc_on_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
@@ -186,7 +171,7 @@ static void hc_on_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
   } else {
     GRPC_ERROR_REF(error);
   }
-  grpc_closure_run(exec_ctx, calld->on_done_recv_trailing_metadata, error);
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_done_recv_trailing_metadata, error);
 }
 
 static void hc_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -460,17 +445,17 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   calld->payload_bytes = NULL;
   calld->send_message_blocked = false;
   grpc_slice_buffer_init(&calld->slices);
-  grpc_closure_init(&calld->hc_on_recv_initial_metadata,
+  GRPC_CLOSURE_INIT(&calld->hc_on_recv_initial_metadata,
                     hc_on_recv_initial_metadata, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->hc_on_recv_trailing_metadata,
+  GRPC_CLOSURE_INIT(&calld->hc_on_recv_trailing_metadata,
                     hc_on_recv_trailing_metadata, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->hc_on_complete, hc_on_complete, elem,
+  GRPC_CLOSURE_INIT(&calld->hc_on_complete, hc_on_complete, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->got_slice, got_slice, elem,
+  GRPC_CLOSURE_INIT(&calld->got_slice, got_slice, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->send_done, send_done, elem,
+  GRPC_CLOSURE_INIT(&calld->send_done, send_done, elem,
                     grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
diff --git a/src/core/ext/filters/http/client/http_client_filter.h b/src/core/ext/filters/http/client/http_client_filter.h
index 6e1eb3937b..ec8177c436 100644
--- a/src/core/ext/filters/http/client/http_client_filter.h
+++ b/src/core/ext/filters/http/client/http_client_filter.h
@@ -1,32 +1,17 @@
 /*
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/http/http_filters_plugin.c b/src/core/ext/filters/http/http_filters_plugin.c
index 856a7dbd91..a5c1b92054 100644
--- a/src/core/ext/filters/http/http_filters_plugin.c
+++ b/src/core/ext/filters/http/http_filters_plugin.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -80,7 +65,7 @@ static bool maybe_add_required_filter(grpc_exec_ctx *exec_ctx,
 }
 
 void grpc_http_filters_init(void) {
-  grpc_register_tracer("compression", &grpc_compression_trace);
+  grpc_register_tracer(&grpc_compression_trace);
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
                                    GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
                                    maybe_add_optional_filter, &compress_filter);
diff --git a/src/core/ext/filters/http/message_compress/message_compress_filter.c b/src/core/ext/filters/http/message_compress/message_compress_filter.c
index 5a54a6ed15..71a8bc5bec 100644
--- a/src/core/ext/filters/http/message_compress/message_compress_filter.c
+++ b/src/core/ext/filters/http/message_compress/message_compress_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -270,6 +255,23 @@ static void continue_send_message(grpc_exec_ctx *exec_ctx,
   }
 }
 
+static void handle_send_message_batch(grpc_exec_ctx *exec_ctx,
+                                      grpc_call_element *elem,
+                                      grpc_transport_stream_op_batch *op,
+                                      bool has_compression_algorithm) {
+  call_data *calld = elem->call_data;
+  if (!skip_compression(elem, op->payload->send_message.send_message->flags,
+                        has_compression_algorithm)) {
+    calld->send_op = op;
+    calld->send_length = op->payload->send_message.send_message->length;
+    calld->send_flags = op->payload->send_message.send_message->flags;
+    continue_send_message(exec_ctx, elem);
+  } else {
+    /* pass control down the stack */
+    grpc_call_next_op(exec_ctx, elem, op);
+  }
+}
+
 static void compress_start_transport_stream_op_batch(
     grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     grpc_transport_stream_op_batch *op) {
@@ -322,8 +324,9 @@ static void compress_start_transport_stream_op_batch(
         goto retry_send_im;
       }
       if (cur != INITIAL_METADATA_UNSEEN) {
-        grpc_call_next_op(exec_ctx, elem,
-                          (grpc_transport_stream_op_batch *)cur);
+        handle_send_message_batch(exec_ctx, elem,
+                                  (grpc_transport_stream_op_batch *)cur,
+                                  has_compression_algorithm);
       }
     }
   }
@@ -340,17 +343,8 @@ static void compress_start_transport_stream_op_batch(
         break;
       case HAS_COMPRESSION_ALGORITHM:
       case NO_COMPRESSION_ALGORITHM:
-        if (!skip_compression(elem,
-                              op->payload->send_message.send_message->flags,
-                              cur == HAS_COMPRESSION_ALGORITHM)) {
-          calld->send_op = op;
-          calld->send_length = op->payload->send_message.send_message->length;
-          calld->send_flags = op->payload->send_message.send_message->flags;
-          continue_send_message(exec_ctx, elem);
-        } else {
-          /* pass control down the stack */
-          grpc_call_next_op(exec_ctx, elem, op);
-        }
+        handle_send_message_batch(exec_ctx, elem, op,
+                                  cur == HAS_COMPRESSION_ALGORITHM);
         break;
       default:
         if (cur & CANCELLED_BIT) {
@@ -379,9 +373,9 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
 
   /* initialize members */
   grpc_slice_buffer_init(&calld->slices);
-  grpc_closure_init(&calld->got_slice, got_slice, elem,
+  GRPC_CLOSURE_INIT(&calld->got_slice, got_slice, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->send_done, send_done, elem,
+  GRPC_CLOSURE_INIT(&calld->send_done, send_done, elem,
                     grpc_schedule_on_exec_ctx);
 
   return GRPC_ERROR_NONE;
diff --git a/src/core/ext/filters/http/message_compress/message_compress_filter.h b/src/core/ext/filters/http/message_compress/message_compress_filter.h
index 135da4da62..c121a391eb 100644
--- a/src/core/ext/filters/http/message_compress/message_compress_filter.h
+++ b/src/core/ext/filters/http/message_compress/message_compress_filter.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/http/server/http_server_filter.c b/src/core/ext/filters/http/server/http_server_filter.c
index 9e495f4d42..b145f12aff 100644
--- a/src/core/ext/filters/http/server/http_server_filter.c
+++ b/src/core/ext/filters/http/server/http_server_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -284,7 +269,7 @@ static void hs_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
   } else {
     GRPC_ERROR_REF(err);
   }
-  grpc_closure_run(exec_ctx, calld->on_done_recv, err);
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_done_recv, err);
 }
 
 static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -296,11 +281,11 @@ static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
     *calld->pp_recv_message = calld->payload_bin_delivered
                                   ? NULL
                                   : (grpc_byte_stream *)&calld->read_stream;
-    grpc_closure_run(exec_ctx, calld->recv_message_ready, GRPC_ERROR_REF(err));
+    GRPC_CLOSURE_RUN(exec_ctx, calld->recv_message_ready, GRPC_ERROR_REF(err));
     calld->recv_message_ready = NULL;
     calld->payload_bin_delivered = true;
   }
-  grpc_closure_run(exec_ctx, calld->on_complete, GRPC_ERROR_REF(err));
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_complete, GRPC_ERROR_REF(err));
 }
 
 static void hs_recv_message_ready(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -311,7 +296,7 @@ static void hs_recv_message_ready(grpc_exec_ctx *exec_ctx, void *user_data,
     /* do nothing. This is probably a GET request, and payload will be returned
     in hs_on_complete callback. */
   } else {
-    grpc_closure_run(exec_ctx, calld->recv_message_ready, GRPC_ERROR_REF(err));
+    GRPC_CLOSURE_RUN(exec_ctx, calld->recv_message_ready, GRPC_ERROR_REF(err));
   }
 }
 
@@ -398,11 +383,11 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   /* grab pointers to our data from the call element */
   call_data *calld = elem->call_data;
   /* initialize members */
-  grpc_closure_init(&calld->hs_on_recv, hs_on_recv, elem,
+  GRPC_CLOSURE_INIT(&calld->hs_on_recv, hs_on_recv, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->hs_on_complete, hs_on_complete, elem,
+  GRPC_CLOSURE_INIT(&calld->hs_on_complete, hs_on_complete, elem,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&calld->hs_recv_message_ready, hs_recv_message_ready, elem,
+  GRPC_CLOSURE_INIT(&calld->hs_recv_message_ready, hs_recv_message_ready, elem,
                     grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&calld->read_slice_buffer);
   return GRPC_ERROR_NONE;
diff --git a/src/core/ext/filters/http/server/http_server_filter.h b/src/core/ext/filters/http/server/http_server_filter.h
index 8a2b2196ae..c0f678a329 100644
--- a/src/core/ext/filters/http/server/http_server_filter.h
+++ b/src/core/ext/filters/http/server/http_server_filter.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/load_reporting/load_reporting.c b/src/core/ext/filters/load_reporting/load_reporting.c
index 4e9d0937ae..9745763c91 100644
--- a/src/core/ext/filters/load_reporting/load_reporting.c
+++ b/src/core/ext/filters/load_reporting/load_reporting.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -65,11 +50,7 @@ static bool maybe_add_load_reporting_filter(grpc_exec_ctx *exec_ctx,
 }
 
 grpc_arg grpc_load_reporting_enable_arg() {
-  grpc_arg arg;
-  arg.type = GRPC_ARG_INTEGER;
-  arg.key = GRPC_ARG_ENABLE_LOAD_REPORTING;
-  arg.value.integer = 1;
-  return arg;
+  return grpc_channel_arg_integer_create(GRPC_ARG_ENABLE_LOAD_REPORTING, 1);
 }
 
 /* Plugin registration */
diff --git a/src/core/ext/filters/load_reporting/load_reporting.h b/src/core/ext/filters/load_reporting/load_reporting.h
index e05a9dcc71..fc04d2826a 100644
--- a/src/core/ext/filters/load_reporting/load_reporting.h
+++ b/src/core/ext/filters/load_reporting/load_reporting.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/load_reporting/load_reporting_filter.c b/src/core/ext/filters/load_reporting/load_reporting_filter.c
index 75a9a56687..08474efb2e 100644
--- a/src/core/ext/filters/load_reporting/load_reporting_filter.c
+++ b/src/core/ext/filters/load_reporting/load_reporting_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -105,7 +90,7 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
                                   const grpc_call_element_args *args) {
   call_data *calld = elem->call_data;
   calld->id = (intptr_t)args->call_stack;
-  grpc_closure_init(&calld->on_initial_md_ready, on_initial_md_ready, elem,
+  GRPC_CLOSURE_INIT(&calld->on_initial_md_ready, on_initial_md_ready, elem,
                     grpc_schedule_on_exec_ctx);
 
   /* TODO(dgq): do something with the data
diff --git a/src/core/ext/filters/load_reporting/load_reporting_filter.h b/src/core/ext/filters/load_reporting/load_reporting_filter.h
index da884a1479..1a5424e43a 100644
--- a/src/core/ext/filters/load_reporting/load_reporting_filter.h
+++ b/src/core/ext/filters/load_reporting/load_reporting_filter.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/filters/max_age/max_age_filter.c b/src/core/ext/filters/max_age/max_age_filter.c
index a9d91e2f80..7d748b9c32 100644
--- a/src/core/ext/filters/max_age/max_age_filter.c
+++ b/src/core/ext/filters/max_age/max_age_filter.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -123,7 +108,7 @@ static void decrease_call_count(grpc_exec_ctx* exec_ctx, channel_data* chand) {
 
 static void start_max_idle_timer_after_init(grpc_exec_ctx* exec_ctx, void* arg,
                                             grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   /* Decrease call_count. If there are no active calls at this time,
      max_idle_timer will start here. If the number of active calls is not 0,
      max_idle_timer will start after all the active calls end. */
@@ -134,7 +119,7 @@ static void start_max_idle_timer_after_init(grpc_exec_ctx* exec_ctx, void* arg,
 
 static void start_max_age_timer_after_init(grpc_exec_ctx* exec_ctx, void* arg,
                                            grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   gpr_mu_lock(&chand->max_age_timer_mu);
   chand->max_age_timer_pending = true;
   GRPC_CHANNEL_STACK_REF(chand->channel_stack, "max_age max_age_timer");
@@ -155,7 +140,7 @@ static void start_max_age_timer_after_init(grpc_exec_ctx* exec_ctx, void* arg,
 static void start_max_age_grace_timer_after_goaway_op(grpc_exec_ctx* exec_ctx,
                                                       void* arg,
                                                       grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   gpr_mu_lock(&chand->max_age_timer_mu);
   chand->max_age_grace_timer_pending = true;
   GRPC_CHANNEL_STACK_REF(chand->channel_stack, "max_age max_age_grace_timer");
@@ -171,7 +156,7 @@ static void start_max_age_grace_timer_after_goaway_op(grpc_exec_ctx* exec_ctx,
 
 static void close_max_idle_channel(grpc_exec_ctx* exec_ctx, void* arg,
                                    grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   if (error == GRPC_ERROR_NONE) {
     /* Prevent the max idle timer from being set again */
     gpr_atm_no_barrier_fetch_add(&chand->call_count, 1);
@@ -191,7 +176,7 @@ static void close_max_idle_channel(grpc_exec_ctx* exec_ctx, void* arg,
 
 static void close_max_age_channel(grpc_exec_ctx* exec_ctx, void* arg,
                                   grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   gpr_mu_lock(&chand->max_age_timer_mu);
   chand->max_age_timer_pending = false;
   gpr_mu_unlock(&chand->max_age_timer_mu);
@@ -215,7 +200,7 @@ static void close_max_age_channel(grpc_exec_ctx* exec_ctx, void* arg,
 
 static void force_close_max_age_channel(grpc_exec_ctx* exec_ctx, void* arg,
                                         grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   gpr_mu_lock(&chand->max_age_timer_mu);
   chand->max_age_grace_timer_pending = false;
   gpr_mu_unlock(&chand->max_age_timer_mu);
@@ -235,7 +220,7 @@ static void force_close_max_age_channel(grpc_exec_ctx* exec_ctx, void* arg,
 
 static void channel_connectivity_changed(grpc_exec_ctx* exec_ctx, void* arg,
                                          grpc_error* error) {
-  channel_data* chand = arg;
+  channel_data* chand = (channel_data*)arg;
   if (chand->connectivity_state != GRPC_CHANNEL_SHUTDOWN) {
     grpc_transport_op* op = grpc_make_transport_op(NULL);
     op->on_connectivity_state_change = &chand->channel_connectivity_changed,
@@ -279,7 +264,7 @@ static int add_random_max_connection_age_jitter(int value) {
 static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
                                   grpc_call_element* elem,
                                   const grpc_call_element_args* args) {
-  channel_data* chand = elem->channel_data;
+  channel_data* chand = (channel_data*)elem->channel_data;
   increase_call_count(exec_ctx, chand);
   return GRPC_ERROR_NONE;
 }
@@ -296,7 +281,7 @@ static void destroy_call_elem(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
 static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
                                      grpc_channel_element* elem,
                                      grpc_channel_element_args* args) {
-  channel_data* chand = elem->channel_data;
+  channel_data* chand = (channel_data*)elem->channel_data;
   gpr_mu_init(&chand->max_age_timer_mu);
   chand->max_age_timer_pending = false;
   chand->max_age_grace_timer_pending = false;
@@ -344,23 +329,23 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
                            : gpr_time_from_millis(value, GPR_TIMESPAN);
     }
   }
-  grpc_closure_init(&chand->close_max_idle_channel, close_max_idle_channel,
+  GRPC_CLOSURE_INIT(&chand->close_max_idle_channel, close_max_idle_channel,
                     chand, grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->close_max_age_channel, close_max_age_channel, chand,
+  GRPC_CLOSURE_INIT(&chand->close_max_age_channel, close_max_age_channel, chand,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->force_close_max_age_channel,
+  GRPC_CLOSURE_INIT(&chand->force_close_max_age_channel,
                     force_close_max_age_channel, chand,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->start_max_idle_timer_after_init,
+  GRPC_CLOSURE_INIT(&chand->start_max_idle_timer_after_init,
                     start_max_idle_timer_after_init, chand,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->start_max_age_timer_after_init,
+  GRPC_CLOSURE_INIT(&chand->start_max_age_timer_after_init,
                     start_max_age_timer_after_init, chand,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->start_max_age_grace_timer_after_goaway_op,
+  GRPC_CLOSURE_INIT(&chand->start_max_age_grace_timer_after_goaway_op,
                     start_max_age_grace_timer_after_goaway_op, chand,
                     grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&chand->channel_connectivity_changed,
+  GRPC_CLOSURE_INIT(&chand->channel_connectivity_changed,
                     channel_connectivity_changed, chand,
                     grpc_schedule_on_exec_ctx);
 
@@ -375,7 +360,7 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
        initialization is done. */
     GRPC_CHANNEL_STACK_REF(chand->channel_stack,
                            "max_age start_max_age_timer_after_init");
-    grpc_closure_sched(exec_ctx, &chand->start_max_age_timer_after_init,
+    GRPC_CLOSURE_SCHED(exec_ctx, &chand->start_max_age_timer_after_init,
                        GRPC_ERROR_NONE);
   }
 
@@ -386,7 +371,7 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
       0) {
     GRPC_CHANNEL_STACK_REF(chand->channel_stack,
                            "max_age start_max_idle_timer_after_init");
-    grpc_closure_sched(exec_ctx, &chand->start_max_idle_timer_after_init,
+    GRPC_CLOSURE_SCHED(exec_ctx, &chand->start_max_idle_timer_after_init,
                        GRPC_ERROR_NONE);
   }
   return GRPC_ERROR_NONE;
diff --git a/src/core/ext/filters/max_age/max_age_filter.h b/src/core/ext/filters/max_age/max_age_filter.h
index ed2015297a..68fb4a4ca5 100644
--- a/src/core/ext/filters/max_age/max_age_filter.h
+++ b/src/core/ext/filters/max_age/max_age_filter.h
@@ -1,32 +1,17 @@
 //
-// Copyright 2017, Google Inc.
-// All rights reserved.
+// Copyright 2017 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 
 #ifndef GRPC_CORE_EXT_FILTERS_MAX_AGE_MAX_AGE_FILTER_H
diff --git a/src/core/ext/filters/message_size/message_size_filter.c b/src/core/ext/filters/message_size/message_size_filter.c
index b615116965..846c7df69a 100644
--- a/src/core/ext/filters/message_size/message_size_filter.c
+++ b/src/core/ext/filters/message_size/message_size_filter.c
@@ -1,32 +1,17 @@
 //
-// Copyright 2016, Google Inc.
-// All rights reserved.
+// Copyright 2016 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 
 #include "src/core/ext/filters/message_size/message_size_filter.h"
@@ -75,7 +60,8 @@ static void* message_size_limits_create_from_json(const grpc_json* json) {
       if (max_response_message_bytes == -1) return NULL;
     }
   }
-  message_size_limits* value = gpr_malloc(sizeof(message_size_limits));
+  message_size_limits* value =
+      (message_size_limits*)gpr_malloc(sizeof(message_size_limits));
   value->max_send_size = max_request_message_bytes;
   value->max_recv_size = max_response_message_bytes;
   return value;
@@ -103,8 +89,8 @@ typedef struct channel_data {
 // receive message size.
 static void recv_message_ready(grpc_exec_ctx* exec_ctx, void* user_data,
                                grpc_error* error) {
-  grpc_call_element* elem = user_data;
-  call_data* calld = elem->call_data;
+  grpc_call_element* elem = (grpc_call_element*)user_data;
+  call_data* calld = (call_data*)elem->call_data;
   if (*calld->recv_message != NULL && calld->limits.max_recv_size >= 0 &&
       (*calld->recv_message)->length > (size_t)calld->limits.max_recv_size) {
     char* message_string;
@@ -125,14 +111,14 @@ static void recv_message_ready(grpc_exec_ctx* exec_ctx, void* user_data,
     GRPC_ERROR_REF(error);
   }
   // Invoke the next callback.
-  grpc_closure_run(exec_ctx, calld->next_recv_message_ready, error);
+  GRPC_CLOSURE_RUN(exec_ctx, calld->next_recv_message_ready, error);
 }
 
 // Start transport stream op.
 static void start_transport_stream_op_batch(
     grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     grpc_transport_stream_op_batch* op) {
-  call_data* calld = elem->call_data;
+  call_data* calld = (call_data*)elem->call_data;
   // Check max send message size.
   if (op->send_message && calld->limits.max_send_size >= 0 &&
       op->payload->send_message.send_message->length >
@@ -164,10 +150,10 @@ static void start_transport_stream_op_batch(
 static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
                                   grpc_call_element* elem,
                                   const grpc_call_element_args* args) {
-  channel_data* chand = elem->channel_data;
-  call_data* calld = elem->call_data;
+  channel_data* chand = (channel_data*)elem->channel_data;
+  call_data* calld = (call_data*)elem->call_data;
   calld->next_recv_message_ready = NULL;
-  grpc_closure_init(&calld->recv_message_ready, recv_message_ready, elem,
+  GRPC_CLOSURE_INIT(&calld->recv_message_ready, recv_message_ready, elem,
                     grpc_schedule_on_exec_ctx);
   // Get max sizes from channel data, then merge in per-method config values.
   // Note: Per-method config is only available on the client, so we
@@ -175,8 +161,9 @@ static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
   // size to the receive limit.
   calld->limits = chand->limits;
   if (chand->method_limit_table != NULL) {
-    message_size_limits* limits = grpc_method_config_table_get(
-        exec_ctx, chand->method_limit_table, args->path);
+    message_size_limits* limits =
+        (message_size_limits*)grpc_method_config_table_get(
+            exec_ctx, chand->method_limit_table, args->path);
     if (limits != NULL) {
       if (limits->max_send_size >= 0 &&
           (limits->max_send_size < calld->limits.max_send_size ||
@@ -235,7 +222,7 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
                                      grpc_channel_element* elem,
                                      grpc_channel_element_args* args) {
   GPR_ASSERT(!args->is_last);
-  channel_data* chand = elem->channel_data;
+  channel_data* chand = (channel_data*)elem->channel_data;
   chand->limits = get_message_size_limits(args->channel_args);
   // Get method config table from channel args.
   const grpc_arg* channel_arg =
@@ -258,7 +245,7 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
 // Destructor for channel_data.
 static void destroy_channel_elem(grpc_exec_ctx* exec_ctx,
                                  grpc_channel_element* elem) {
-  channel_data* chand = elem->channel_data;
+  channel_data* chand = (channel_data*)elem->channel_data;
   grpc_slice_hash_table_unref(exec_ctx, chand->method_limit_table);
 }
 
diff --git a/src/core/ext/filters/message_size/message_size_filter.h b/src/core/ext/filters/message_size/message_size_filter.h
index 83980e738c..d3667f7003 100644
--- a/src/core/ext/filters/message_size/message_size_filter.h
+++ b/src/core/ext/filters/message_size/message_size_filter.h
@@ -1,32 +1,17 @@
 //
-// Copyright 2016, Google Inc.
-// All rights reserved.
+// Copyright 2016 gRPC authors.
 //
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
 //
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
+//     http://www.apache.org/licenses/LICENSE-2.0
 //
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 //
 
 #ifndef GRPC_CORE_EXT_FILTERS_MESSAGE_SIZE_MESSAGE_SIZE_FILTER_H
diff --git a/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.c b/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.c
new file mode 100644
index 0000000000..b4d2cb4b8c
--- /dev/null
+++ b/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.c
@@ -0,0 +1,208 @@
+//
+// Copyright 2017 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "src/core/ext/filters/workarounds/workaround_cronet_compression_filter.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+
+#include "src/core/ext/filters/workarounds/workaround_utils.h"
+#include "src/core/lib/channel/channel_stack_builder.h"
+#include "src/core/lib/surface/channel_init.h"
+#include "src/core/lib/transport/metadata.h"
+
+typedef struct call_data {
+  // Receive closures are chained: we inject this closure as the
+  // recv_initial_metadata_ready up-call on transport_stream_op, and remember to
+  // call our next_recv_initial_metadata_ready member after handling it.
+  grpc_closure recv_initial_metadata_ready;
+  // Used by recv_initial_metadata_ready.
+  grpc_metadata_batch* recv_initial_metadata;
+  // Original recv_initial_metadata_ready callback, invoked after our own.
+  grpc_closure* next_recv_initial_metadata_ready;
+
+  // Marks whether the workaround is active
+  bool workaround_active;
+} call_data;
+
+// Find the user agent metadata element in the batch
+static bool get_user_agent_mdelem(const grpc_metadata_batch* batch,
+                                  grpc_mdelem* md) {
+  if (batch->idx.named.user_agent != NULL) {
+    *md = batch->idx.named.user_agent->md;
+    return true;
+  }
+  return false;
+}
+
+// Callback invoked when we receive an initial metadata.
+static void recv_initial_metadata_ready(grpc_exec_ctx* exec_ctx,
+                                        void* user_data, grpc_error* error) {
+  grpc_call_element* elem = (grpc_call_element*)user_data;
+  call_data* calld = (call_data*)elem->call_data;
+
+  if (GRPC_ERROR_NONE == error) {
+    grpc_mdelem md;
+    if (get_user_agent_mdelem(calld->recv_initial_metadata, &md)) {
+      grpc_workaround_user_agent_md* user_agent_md = grpc_parse_user_agent(md);
+      if (user_agent_md
+              ->workaround_active[GRPC_WORKAROUND_ID_CRONET_COMPRESSION]) {
+        calld->workaround_active = true;
+      }
+    }
+  }
+
+  // Invoke the next callback.
+  GRPC_CLOSURE_RUN(exec_ctx, calld->next_recv_initial_metadata_ready,
+                   GRPC_ERROR_REF(error));
+}
+
+// Start transport stream op.
+static void start_transport_stream_op_batch(
+    grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
+    grpc_transport_stream_op_batch* op) {
+  call_data* calld = (call_data*)elem->call_data;
+
+  // Inject callback for receiving initial metadata
+  if (op->recv_initial_metadata) {
+    calld->next_recv_initial_metadata_ready =
+        op->payload->recv_initial_metadata.recv_initial_metadata_ready;
+    op->payload->recv_initial_metadata.recv_initial_metadata_ready =
+        &calld->recv_initial_metadata_ready;
+    calld->recv_initial_metadata =
+        op->payload->recv_initial_metadata.recv_initial_metadata;
+  }
+
+  if (op->send_message) {
+    /* Send message happens after client's user-agent (initial metadata) is
+     * received, so workaround_active must be set already */
+    if (calld->workaround_active) {
+      op->payload->send_message.send_message->flags |= GRPC_WRITE_NO_COMPRESS;
+    }
+  }
+
+  // Chain to the next filter.
+  grpc_call_next_op(exec_ctx, elem, op);
+}
+
+// Constructor for call_data.
+static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
+                                  grpc_call_element* elem,
+                                  const grpc_call_element_args* args) {
+  call_data* calld = (call_data*)elem->call_data;
+  calld->next_recv_initial_metadata_ready = NULL;
+  calld->workaround_active = false;
+  GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
+                    recv_initial_metadata_ready, elem,
+                    grpc_schedule_on_exec_ctx);
+  return GRPC_ERROR_NONE;
+}
+
+// Destructor for call_data.
+static void destroy_call_elem(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
+                              const grpc_call_final_info* final_info,
+                              grpc_closure* ignored) {}
+
+// Constructor for channel_data.
+static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
+                                     grpc_channel_element* elem,
+                                     grpc_channel_element_args* args) {
+  return GRPC_ERROR_NONE;
+}
+
+// Destructor for channel_data.
+static void destroy_channel_elem(grpc_exec_ctx* exec_ctx,
+                                 grpc_channel_element* elem) {}
+
+// Parse the user agent
+static bool parse_user_agent(grpc_mdelem md) {
+  const char grpc_objc_specifier[] = "grpc-objc/";
+  const size_t grpc_objc_specifier_len = sizeof(grpc_objc_specifier) - 1;
+  const char cronet_specifier[] = "cronet_http";
+  const size_t cronet_specifier_len = sizeof(cronet_specifier) - 1;
+
+  char* user_agent_str = grpc_slice_to_c_string(GRPC_MDVALUE(md));
+  bool grpc_objc_specifier_seen = false;
+  bool cronet_specifier_seen = false;
+  char *major_version_str = user_agent_str, *minor_version_str;
+  long major_version, minor_version;
+
+  char* head = strtok(user_agent_str, " ");
+  while (head != NULL) {
+    if (!grpc_objc_specifier_seen &&
+        0 == strncmp(head, grpc_objc_specifier, grpc_objc_specifier_len)) {
+      major_version_str = head + grpc_objc_specifier_len;
+      grpc_objc_specifier_seen = true;
+    } else if (grpc_objc_specifier_seen &&
+               0 == strncmp(head, cronet_specifier, cronet_specifier_len)) {
+      cronet_specifier_seen = true;
+      break;
+    }
+
+    head = strtok(NULL, " ");
+  }
+  if (grpc_objc_specifier_seen) {
+    major_version_str = strtok(major_version_str, ".");
+    minor_version_str = strtok(NULL, ".");
+    major_version = atol(major_version_str);
+    minor_version = atol(minor_version_str);
+  }
+
+  gpr_free(user_agent_str);
+  return (grpc_objc_specifier_seen && cronet_specifier_seen &&
+          (major_version < 1 || (major_version == 1 && minor_version <= 3)));
+}
+
+const grpc_channel_filter grpc_workaround_cronet_compression_filter = {
+    start_transport_stream_op_batch,
+    grpc_channel_next_op,
+    sizeof(call_data),
+    init_call_elem,
+    grpc_call_stack_ignore_set_pollset_or_pollset_set,
+    destroy_call_elem,
+    0,
+    init_channel_elem,
+    destroy_channel_elem,
+    grpc_call_next_get_peer,
+    grpc_channel_next_get_info,
+    "workaround_cronet_compression"};
+
+static bool register_workaround_cronet_compression(
+    grpc_exec_ctx* exec_ctx, grpc_channel_stack_builder* builder, void* arg) {
+  const grpc_channel_args* channel_args =
+      grpc_channel_stack_builder_get_channel_arguments(builder);
+  const grpc_arg* a = grpc_channel_args_find(
+      channel_args, GRPC_ARG_WORKAROUND_CRONET_COMPRESSION);
+  if (a == NULL) {
+    return true;
+  }
+  if (grpc_channel_arg_get_bool(a, false) == false) {
+    return true;
+  }
+  return grpc_channel_stack_builder_prepend_filter(
+      builder, &grpc_workaround_cronet_compression_filter, NULL, NULL);
+}
+
+void grpc_workaround_cronet_compression_filter_init(void) {
+  grpc_channel_init_register_stage(
+      GRPC_SERVER_CHANNEL, GRPC_WORKAROUND_PRIORITY_HIGH,
+      register_workaround_cronet_compression, NULL);
+  grpc_register_workaround(GRPC_WORKAROUND_ID_CRONET_COMPRESSION,
+                           parse_user_agent);
+}
+
+void grpc_workaround_cronet_compression_filter_shutdown(void) {}
diff --git a/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.h b/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.h
new file mode 100644
index 0000000000..9dae4f0734
--- /dev/null
+++ b/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.h
@@ -0,0 +1,25 @@
+//
+// Copyright 2017 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_CRONET_COMPRESSION_FILTER_H
+#define GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_CRONET_COMPRESSION_FILTER_H
+
+#include "src/core/lib/channel/channel_stack.h"
+
+extern const grpc_channel_filter grpc_workaround_cronet_compression_filter;
+
+#endif /* GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_CRONET_COMPRESSION_FILTER_H \
+        */
diff --git a/src/core/ext/filters/workarounds/workaround_utils.c b/src/core/ext/filters/workarounds/workaround_utils.c
new file mode 100644
index 0000000000..e600fbee67
--- /dev/null
+++ b/src/core/ext/filters/workarounds/workaround_utils.c
@@ -0,0 +1,51 @@
+//
+// Copyright 2017 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#include "src/core/ext/filters/workarounds/workaround_utils.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+user_agent_parser ua_parser[GRPC_MAX_WORKAROUND_ID];
+
+static void destroy_user_agent_md(void *user_agent_md) {
+  gpr_free(user_agent_md);
+}
+
+grpc_workaround_user_agent_md *grpc_parse_user_agent(grpc_mdelem md) {
+  grpc_workaround_user_agent_md *user_agent_md =
+      (grpc_workaround_user_agent_md *)grpc_mdelem_get_user_data(
+          md, destroy_user_agent_md);
+
+  if (NULL != user_agent_md) {
+    return user_agent_md;
+  }
+  user_agent_md = (grpc_workaround_user_agent_md *)gpr_malloc(
+      sizeof(grpc_workaround_user_agent_md));
+  for (int i = 0; i < GRPC_MAX_WORKAROUND_ID; i++) {
+    if (ua_parser[i]) {
+      user_agent_md->workaround_active[i] = ua_parser[i](md);
+    }
+  }
+  grpc_mdelem_set_user_data(md, destroy_user_agent_md, (void *)user_agent_md);
+
+  return user_agent_md;
+}
+
+void grpc_register_workaround(uint32_t id, user_agent_parser parser) {
+  GPR_ASSERT(id < GRPC_MAX_WORKAROUND_ID);
+  ua_parser[id] = parser;
+}
diff --git a/src/core/ext/filters/workarounds/workaround_utils.h b/src/core/ext/filters/workarounds/workaround_utils.h
new file mode 100644
index 0000000000..2ad7a876d5
--- /dev/null
+++ b/src/core/ext/filters/workarounds/workaround_utils.h
@@ -0,0 +1,37 @@
+//
+// Copyright 2017 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_UTILS_H
+#define GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_UTILS_H
+
+#include <grpc/support/workaround_list.h>
+
+#include "src/core/lib/transport/metadata.h"
+
+#define GRPC_WORKAROUND_PRIORITY_HIGH 10001
+#define GRPC_WORKAROUND_PROIRITY_LOW 9999
+
+typedef struct grpc_workaround_user_agent_md {
+  bool workaround_active[GRPC_MAX_WORKAROUND_ID];
+} grpc_workaround_user_agent_md;
+
+grpc_workaround_user_agent_md *grpc_parse_user_agent(grpc_mdelem md);
+
+typedef bool (*user_agent_parser)(grpc_mdelem);
+
+void grpc_register_workaround(uint32_t id, user_agent_parser parser);
+
+#endif /* GRPC_CORE_EXT_FILTERS_WORKAROUNDS_WORKAROUND_UTILS_H */
diff --git a/src/core/ext/transport/chttp2/alpn/alpn.c b/src/core/ext/transport/chttp2/alpn/alpn.c
index 55710dc5ae..ca2e801ec8 100644
--- a/src/core/ext/transport/chttp2/alpn/alpn.c
+++ b/src/core/ext/transport/chttp2/alpn/alpn.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/alpn/alpn.h b/src/core/ext/transport/chttp2/alpn/alpn.h
index 1316770f11..379af4b24c 100644
--- a/src/core/ext/transport/chttp2/alpn/alpn.h
+++ b/src/core/ext/transport/chttp2/alpn/alpn.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/client/chttp2_connector.c b/src/core/ext/transport/chttp2/client/chttp2_connector.c
index e645eda7e3..983691bbad 100644
--- a/src/core/ext/transport/chttp2/client/chttp2_connector.c
+++ b/src/core/ext/transport/chttp2/client/chttp2_connector.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -139,7 +124,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   }
   grpc_closure *notify = c->notify;
   c->notify = NULL;
-  grpc_closure_sched(exec_ctx, notify, error);
+  GRPC_CLOSURE_SCHED(exec_ctx, notify, error);
   grpc_handshake_manager_destroy(exec_ctx, c->handshake_mgr);
   c->handshake_mgr = NULL;
   gpr_mu_unlock(&c->mu);
@@ -171,7 +156,7 @@ static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
     memset(c->result, 0, sizeof(*c->result));
     grpc_closure *notify = c->notify;
     c->notify = NULL;
-    grpc_closure_sched(exec_ctx, notify, error);
+    GRPC_CLOSURE_SCHED(exec_ctx, notify, error);
     if (c->endpoint != NULL) {
       grpc_endpoint_shutdown(exec_ctx, c->endpoint, GRPC_ERROR_REF(error));
     }
@@ -199,7 +184,7 @@ static void chttp2_connector_connect(grpc_exec_ctx *exec_ctx,
   c->result = result;
   GPR_ASSERT(c->endpoint == NULL);
   chttp2_connector_ref(con);  // Ref taken for callback.
-  grpc_closure_init(&c->connected, connected, c, grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&c->connected, connected, c, grpc_schedule_on_exec_ctx);
   GPR_ASSERT(!c->connecting);
   c->connecting = true;
   grpc_tcp_client_connect(exec_ctx, &c->connected, &c->endpoint,
diff --git a/src/core/ext/transport/chttp2/client/chttp2_connector.h b/src/core/ext/transport/chttp2/client/chttp2_connector.h
index d55f6ed669..e258892cfc 100644
--- a/src/core/ext/transport/chttp2/client/chttp2_connector.h
+++ b/src/core/ext/transport/chttp2/client/chttp2_connector.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create.c b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
index ad674b8eb4..cccb347bf1 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -69,11 +54,9 @@ static grpc_channel *client_channel_factory_create_channel(
     return NULL;
   }
   // Add channel arg containing the server URI.
-  grpc_arg arg;
-  arg.type = GRPC_ARG_STRING;
-  arg.key = GRPC_ARG_SERVER_URI;
-  arg.value.string =
-      grpc_resolver_factory_add_default_prefix_if_needed(exec_ctx, target);
+  grpc_arg arg = grpc_channel_arg_string_create(
+      GRPC_ARG_SERVER_URI,
+      grpc_resolver_factory_add_default_prefix_if_needed(exec_ctx, target));
   const char *to_remove[] = {GRPC_ARG_SERVER_URI};
   grpc_channel_args *new_args =
       grpc_channel_args_copy_and_add_and_remove(args, to_remove, 1, &arg, 1);
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
index f1069e2c57..0346d50b6c 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -56,10 +41,8 @@ grpc_channel *grpc_insecure_channel_create_from_fd(
   GRPC_API_TRACE("grpc_insecure_channel_create(target=%p, fd=%d, args=%p)", 3,
                  (target, fd, args));
 
-  grpc_arg default_authority_arg;
-  default_authority_arg.type = GRPC_ARG_STRING;
-  default_authority_arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
-  default_authority_arg.value.string = "test.authority";
+  grpc_arg default_authority_arg = grpc_channel_arg_string_create(
+      GRPC_ARG_DEFAULT_AUTHORITY, "test.authority");
   grpc_channel_args *final_args =
       grpc_channel_args_copy_and_add(args, &default_authority_arg, 1);
 
diff --git a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
index 119adfade1..d4580f15f5 100644
--- a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
+++ b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -178,11 +163,9 @@ static grpc_channel *client_channel_factory_create_channel(
     return NULL;
   }
   // Add channel arg containing the server URI.
-  grpc_arg arg;
-  arg.type = GRPC_ARG_STRING;
-  arg.key = GRPC_ARG_SERVER_URI;
-  arg.value.string =
-      grpc_resolver_factory_add_default_prefix_if_needed(exec_ctx, target);
+  grpc_arg arg = grpc_channel_arg_string_create(
+      GRPC_ARG_SERVER_URI,
+      grpc_resolver_factory_add_default_prefix_if_needed(exec_ctx, target));
   const char *to_remove[] = {GRPC_ARG_SERVER_URI};
   grpc_channel_args *new_args =
       grpc_channel_args_copy_and_add_and_remove(args, to_remove, 1, &arg, 1);
diff --git a/src/core/ext/transport/chttp2/server/chttp2_server.c b/src/core/ext/transport/chttp2/server/chttp2_server.c
index a888dc0264..feb95796b3 100644
--- a/src/core/ext/transport/chttp2/server/chttp2_server.c
+++ b/src/core/ext/transport/chttp2/server/chttp2_server.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -127,6 +112,7 @@ static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_endpoint *tcp,
   gpr_mu_lock(&state->mu);
   if (state->shutdown) {
     gpr_mu_unlock(&state->mu);
+    grpc_endpoint_shutdown(exec_ctx, tcp, GRPC_ERROR_NONE);
     grpc_endpoint_destroy(exec_ctx, tcp);
     gpr_free(acceptor);
     return;
@@ -223,7 +209,7 @@ grpc_error *grpc_chttp2_server_add_port(grpc_exec_ctx *exec_ctx,
     goto error;
   }
   state = gpr_zalloc(sizeof(*state));
-  grpc_closure_init(&state->tcp_server_shutdown_complete,
+  GRPC_CLOSURE_INIT(&state->tcp_server_shutdown_complete,
                     tcp_server_shutdown_complete, state,
                     grpc_schedule_on_exec_ctx);
   err = grpc_tcp_server_create(exec_ctx, &state->tcp_server_shutdown_complete,
diff --git a/src/core/ext/transport/chttp2/server/chttp2_server.h b/src/core/ext/transport/chttp2/server/chttp2_server.h
index 2581ebaae9..ed968496f9 100644
--- a/src/core/ext/transport/chttp2/server/chttp2_server.h
+++ b/src/core/ext/transport/chttp2/server/chttp2_server.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
index c219a7d85f..d42b2d123e 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
index 6ab176e8ad..e647067f73 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
index 88c813f3be..5ad63aaf1f 100644
--- a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.c b/src/core/ext/transport/chttp2/transport/bin_decoder.c
index 21bed18c9a..fe7b7e4a42 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.c
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.h b/src/core/ext/transport/chttp2/transport/bin_decoder.h
index 48ffb2ae3b..047b33d587 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.h
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/bin_encoder.c b/src/core/ext/transport/chttp2/transport/bin_encoder.c
index 3b8ab1f17a..42d481b3c0 100644
--- a/src/core/ext/transport/chttp2/transport/bin_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/bin_encoder.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/bin_encoder.h b/src/core/ext/transport/chttp2/transport/bin_encoder.h
index 0f899c8e34..a8f36a345a 100644
--- a/src/core/ext/transport/chttp2/transport/bin_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/bin_encoder.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_plugin.c b/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
index 59b21e3330..78551df9c3 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -36,8 +21,11 @@
 #include "src/core/lib/transport/metadata.h"
 
 void grpc_chttp2_plugin_init(void) {
-  grpc_register_tracer("http", &grpc_http_trace);
-  grpc_register_tracer("flowctl", &grpc_flowctl_trace);
+  grpc_register_tracer(&grpc_http_trace);
+  grpc_register_tracer(&grpc_flowctl_trace);
+#ifndef NDEBUG
+  grpc_register_tracer(&grpc_trace_chttp2_refcount);
+#endif
 }
 
 void grpc_chttp2_plugin_shutdown(void) {}
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index eaf880708f..ffcd715cf6 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -48,9 +33,10 @@
 #include "src/core/ext/transport/chttp2/transport/internal.h"
 #include "src/core/ext/transport/chttp2/transport/varint.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/compression/stream_compression.h"
 #include "src/core/lib/http/parser.h"
+#include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/timer.h"
-#include "src/core/lib/iomgr/workqueue.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
@@ -68,7 +54,7 @@
 #define DEFAULT_CONNECTION_WINDOW_TARGET (1024 * 1024)
 #define MAX_WINDOW 0x7fffffffu
 #define MAX_WRITE_BUFFER_SIZE (64 * 1024 * 1024)
-#define DEFAULT_MAX_HEADER_LIST_SIZE (16 * 1024)
+#define DEFAULT_MAX_HEADER_LIST_SIZE (8 * 1024)
 
 #define DEFAULT_CLIENT_KEEPALIVE_TIME_MS INT_MAX
 #define DEFAULT_CLIENT_KEEPALIVE_TIMEOUT_MS 20000 /* 20 seconds */
@@ -89,8 +75,13 @@ static bool g_default_keepalive_permit_without_calls =
     DEFAULT_KEEPALIVE_PERMIT_WITHOUT_CALLS;
 
 #define MAX_CLIENT_STREAM_ID 0x7fffffffu
-grpc_tracer_flag grpc_http_trace = GRPC_TRACER_INITIALIZER(false);
-grpc_tracer_flag grpc_flowctl_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_http_trace = GRPC_TRACER_INITIALIZER(false, "http");
+grpc_tracer_flag grpc_flowctl_trace = GRPC_TRACER_INITIALIZER(false, "flowctl");
+
+#ifndef NDEBUG
+grpc_tracer_flag grpc_trace_chttp2_refcount =
+    GRPC_TRACER_INITIALIZER(false, "chttp2_refcount");
+#endif
 
 static const grpc_transport_vtable vtable;
 
@@ -107,8 +98,9 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *t,
 static void complete_fetch_locked(grpc_exec_ctx *exec_ctx, void *gs,
                                   grpc_error *error);
 /** Set a transport level setting, and push it to our peer */
-static void push_setting(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                         grpc_chttp2_setting_id id, uint32_t value);
+static void queue_setting_update(grpc_exec_ctx *exec_ctx,
+                                 grpc_chttp2_transport *t,
+                                 grpc_chttp2_setting_id id, uint32_t value);
 
 static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                            grpc_chttp2_stream *s, grpc_error *error);
@@ -228,20 +220,26 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
   gpr_free(t);
 }
 
-#ifdef GRPC_CHTTP2_REFCOUNTING_DEBUG
+#ifndef NDEBUG
 void grpc_chttp2_unref_transport(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t, const char *reason,
                                  const char *file, int line) {
-  gpr_log(GPR_DEBUG, "chttp2:unref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]", t,
-          t->refs.count, t->refs.count - 1, reason, file, line);
+  if (GRPC_TRACER_ON(grpc_trace_chttp2_refcount)) {
+    gpr_atm val = gpr_atm_no_barrier_load(&t->refs.count);
+    gpr_log(GPR_DEBUG, "chttp2:unref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]",
+            t, val, val - 1, reason, file, line);
+  }
   if (!gpr_unref(&t->refs)) return;
   destruct_transport(exec_ctx, t);
 }
 
 void grpc_chttp2_ref_transport(grpc_chttp2_transport *t, const char *reason,
                                const char *file, int line) {
-  gpr_log(GPR_DEBUG, "chttp2:  ref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]", t,
-          t->refs.count, t->refs.count + 1, reason, file, line);
+  if (GRPC_TRACER_ON(grpc_trace_chttp2_refcount)) {
+    gpr_atm val = gpr_atm_no_barrier_load(&t->refs.count);
+    gpr_log(GPR_DEBUG, "chttp2:  ref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]",
+            t, val, val + 1, reason, file, line);
+  }
   gpr_ref(&t->refs);
 }
 #else
@@ -267,7 +265,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->ep = ep;
   /* one ref is for destroy */
   gpr_ref_init(&t->refs, 1);
-  t->combiner = grpc_combiner_create(grpc_endpoint_get_workqueue(ep));
+  t->combiner = grpc_combiner_create();
   t->peer_string = grpc_endpoint_get_peer(ep);
   t->endpoint_reading = 1;
   t->next_stream_id = is_client ? 1 : 2;
@@ -285,32 +283,30 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_slice_buffer_init(&t->outbuf);
   grpc_chttp2_hpack_compressor_init(&t->hpack_compressor);
 
-  grpc_closure_init(&t->write_action, write_action, t,
-                    grpc_schedule_on_exec_ctx);
-  grpc_closure_init(&t->read_action_locked, read_action_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->benign_reclaimer_locked, benign_reclaimer_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->destructive_reclaimer_locked,
+  GRPC_CLOSURE_INIT(&t->read_action_locked, read_action_locked, t,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->benign_reclaimer_locked, benign_reclaimer_locked, t,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->destructive_reclaimer_locked,
                     destructive_reclaimer_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->retry_initiate_ping_locked, retry_initiate_ping_locked,
-                    t, grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->start_bdp_ping_locked, start_bdp_ping_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->finish_bdp_ping_locked, finish_bdp_ping_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->init_keepalive_ping_locked, init_keepalive_ping_locked,
-                    t, grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->start_keepalive_ping_locked,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->retry_initiate_ping_locked, retry_initiate_ping_locked,
+                    t, grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->start_bdp_ping_locked, start_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->finish_bdp_ping_locked, finish_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->init_keepalive_ping_locked, init_keepalive_ping_locked,
+                    t, grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->start_keepalive_ping_locked,
                     start_keepalive_ping_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->finish_keepalive_ping_locked,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->finish_keepalive_ping_locked,
                     finish_keepalive_ping_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
-  grpc_closure_init(&t->keepalive_watchdog_fired_locked,
+                    grpc_combiner_scheduler(t->combiner));
+  GRPC_CLOSURE_INIT(&t->keepalive_watchdog_fired_locked,
                     keepalive_watchdog_fired_locked, t,
-                    grpc_combiner_scheduler(t->combiner, false));
+                    grpc_combiner_scheduler(t->combiner));
 
   grpc_bdp_estimator_init(&t->bdp_estimator, t->peer_string);
   t->last_pid_update = gpr_now(GPR_CLOCK_MONOTONIC);
@@ -353,20 +349,21 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   if (is_client) {
     grpc_slice_buffer_add(&t->outbuf, grpc_slice_from_copied_string(
                                           GRPC_CHTTP2_CLIENT_CONNECT_STRING));
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "initial_write");
+    grpc_chttp2_initiate_write(exec_ctx, t, "initial_write");
   }
 
   /* configure http2 the way we like it */
   if (is_client) {
-    push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_ENABLE_PUSH, 0);
-    push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 0);
+    queue_setting_update(exec_ctx, t, GRPC_CHTTP2_SETTINGS_ENABLE_PUSH, 0);
+    queue_setting_update(exec_ctx, t,
+                         GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 0);
   }
-  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
-               DEFAULT_WINDOW);
-  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-               DEFAULT_MAX_HEADER_LIST_SIZE);
-  push_setting(exec_ctx, t,
-               GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA, 1);
+  queue_setting_update(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+                       DEFAULT_WINDOW);
+  queue_setting_update(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+                       DEFAULT_MAX_HEADER_LIST_SIZE);
+  queue_setting_update(exec_ctx, t,
+                       GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA, 1);
 
   t->ping_policy = (grpc_chttp2_repeated_ping_policy){
       .max_pings_without_data = DEFAULT_MAX_PINGS_BETWEEN_DATA,
@@ -394,6 +391,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
   t->keepalive_permit_without_calls = g_default_keepalive_permit_without_calls;
 
+  t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
+
   if (channel_args) {
     for (i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key,
@@ -476,6 +475,23 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
         t->keepalive_permit_without_calls =
             (uint32_t)grpc_channel_arg_get_integer(
                 &channel_args->args[i], (grpc_integer_options){0, 0, 1});
+      } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_OPTIMIZATION_TARGET)) {
+        if (channel_args->args[i].type != GRPC_ARG_STRING) {
+          gpr_log(GPR_ERROR, "%s should be a string",
+                  GRPC_ARG_OPTIMIZATION_TARGET);
+        } else if (0 == strcmp(channel_args->args[i].value.string, "blend")) {
+          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
+        } else if (0 == strcmp(channel_args->args[i].value.string, "latency")) {
+          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
+        } else if (0 ==
+                   strcmp(channel_args->args[i].value.string, "throughput")) {
+          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT;
+        } else {
+          gpr_log(GPR_ERROR, "%s value '%s' unknown, assuming 'blend'",
+                  GRPC_ARG_OPTIMIZATION_TARGET,
+                  channel_args->args[i].value.string);
+        }
       } else {
         static const struct {
           const char *channel_arg_name;
@@ -518,8 +534,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
               int value = grpc_channel_arg_get_integer(
                   &channel_args->args[i], settings_map[j].integer_options);
               if (value >= 0) {
-                push_setting(exec_ctx, t, settings_map[j].setting_id,
-                             (uint32_t)value);
+                queue_setting_update(exec_ctx, t, settings_map[j].setting_id,
+                                     (uint32_t)value);
               }
             }
             break;
@@ -529,6 +545,11 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     }
   }
 
+  GRPC_CLOSURE_INIT(&t->write_action, write_action, t,
+                    t->opt_target == GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT
+                        ? grpc_executor_scheduler
+                        : grpc_schedule_on_exec_ctx);
+
   t->ping_state.pings_before_data_required =
       t->ping_policy.max_pings_without_data;
   t->ping_state.is_delayed_ping_timer_set = false;
@@ -549,7 +570,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED;
   }
 
-  grpc_chttp2_initiate_write(exec_ctx, t, false, "init");
+  grpc_chttp2_initiate_write(exec_ctx, t, "init");
   post_benign_reclaimer(exec_ctx, t);
 }
 
@@ -567,9 +588,9 @@ static void destroy_transport_locked(grpc_exec_ctx *exec_ctx, void *tp,
 
 static void destroy_transport(grpc_exec_ctx *exec_ctx, grpc_transport *gt) {
   grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
-  grpc_closure_sched(exec_ctx, grpc_closure_create(
-                                   destroy_transport_locked, t,
-                                   grpc_combiner_scheduler(t->combiner, false)),
+  GRPC_CLOSURE_SCHED(exec_ctx,
+                     GRPC_CLOSURE_CREATE(destroy_transport_locked, t,
+                                         grpc_combiner_scheduler(t->combiner)),
                      GRPC_ERROR_NONE);
 }
 
@@ -620,7 +641,7 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
   GRPC_ERROR_UNREF(error);
 }
 
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+#ifndef NDEBUG
 void grpc_chttp2_stream_ref(grpc_chttp2_stream *s, const char *reason) {
   grpc_stream_ref(s->refcount, reason);
 }
@@ -656,13 +677,13 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_data_parser_init(&s->data_parser);
   grpc_slice_buffer_init(&s->flow_controlled_buffer);
   s->deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
-  grpc_closure_init(&s->complete_fetch_locked, complete_fetch_locked, s,
+  GRPC_CLOSURE_INIT(&s->complete_fetch_locked, complete_fetch_locked, s,
                     grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&s->unprocessed_incoming_frames_buffer);
   grpc_slice_buffer_init(&s->frame_storage);
   s->pending_byte_stream = false;
-  grpc_closure_init(&s->reset_byte_stream, reset_byte_stream, s,
-                    grpc_combiner_scheduler(t->combiner, false));
+  GRPC_CLOSURE_INIT(&s->reset_byte_stream, reset_byte_stream, s,
+                    grpc_combiner_scheduler(t->combiner));
 
   GRPC_CHTTP2_REF_TRANSPORT(t, "stream");
 
@@ -733,7 +754,7 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
 
   GPR_TIMER_END("destroy_stream", 0);
 
-  grpc_closure_sched(exec_ctx, s->destroy_stream_arg, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx, s->destroy_stream_arg, GRPC_ERROR_NONE);
 }
 
 static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
@@ -744,9 +765,9 @@ static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_stream *s = (grpc_chttp2_stream *)gs;
 
   s->destroy_stream_arg = then_schedule_closure;
-  grpc_closure_sched(
-      exec_ctx, grpc_closure_init(&s->destroy_stream, destroy_stream_locked, s,
-                                  grpc_combiner_scheduler(t->combiner, false)),
+  GRPC_CLOSURE_SCHED(
+      exec_ctx, GRPC_CLOSURE_INIT(&s->destroy_stream, destroy_stream_locked, s,
+                                  grpc_combiner_scheduler(t->combiner)),
       GRPC_ERROR_NONE);
   GPR_TIMER_END("destroy_stream", 0);
 }
@@ -784,8 +805,6 @@ static const char *write_state_name(grpc_chttp2_write_state st) {
       return "WRITING";
     case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE:
       return "WRITING+MORE";
-    case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER:
-      return "WRITING+MORE+COVERED";
   }
   GPR_UNREACHABLE_CODE(return "UNKNOWN");
 }
@@ -798,7 +817,7 @@ static void set_write_state(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                                  write_state_name(st), reason));
   t->write_state = st;
   if (st == GRPC_CHTTP2_WRITE_STATE_IDLE) {
-    grpc_closure_list_sched(exec_ctx, &t->run_after_write);
+    GRPC_CLOSURE_LIST_SCHED(exec_ctx, &t->run_after_write);
     if (t->close_transport_on_writes_finished != NULL) {
       grpc_error *err = t->close_transport_on_writes_finished;
       t->close_transport_on_writes_finished = NULL;
@@ -808,38 +827,25 @@ static void set_write_state(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 }
 
 void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t,
-                                bool covered_by_poller, const char *reason) {
+                                grpc_chttp2_transport *t, const char *reason) {
   GPR_TIMER_BEGIN("grpc_chttp2_initiate_write", 0);
 
   switch (t->write_state) {
     case GRPC_CHTTP2_WRITE_STATE_IDLE:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING, reason);
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
-          grpc_closure_init(
-              &t->write_action_begin_locked, write_action_begin_locked, t,
-              grpc_combiner_finally_scheduler(t->combiner, covered_by_poller)),
+          GRPC_CLOSURE_INIT(&t->write_action_begin_locked,
+                            write_action_begin_locked, t,
+                            grpc_combiner_finally_scheduler(t->combiner)),
           GRPC_ERROR_NONE);
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING:
-      set_write_state(
-          exec_ctx, t,
-          covered_by_poller
-              ? GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER
-              : GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
-          reason);
+      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
+                      reason);
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE:
-      if (covered_by_poller) {
-        set_write_state(
-            exec_ctx, t,
-            GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER,
-            reason);
-      }
-      break;
-    case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER:
       break;
   }
   GPR_TIMER_END("grpc_chttp2_initiate_write", 0);
@@ -855,10 +861,10 @@ void grpc_chttp2_become_writable(
     case GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK:
       break;
     case GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED:
-      grpc_chttp2_initiate_write(exec_ctx, t, true, reason);
+      grpc_chttp2_initiate_write(exec_ctx, t, reason);
       break;
     case GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED:
-      grpc_chttp2_initiate_write(exec_ctx, t, false, reason);
+      grpc_chttp2_initiate_write(exec_ctx, t, reason);
       break;
   }
 }
@@ -878,12 +884,12 @@ static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *gt,
     case GRPC_CHTTP2_PARTIAL_WRITE:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
                       "begin writing partial");
-      grpc_closure_sched(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
       break;
     case GRPC_CHTTP2_FULL_WRITE:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
                       "begin writing");
-      grpc_closure_sched(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
       break;
   }
   GPR_TIMER_END("write_action_begin_locked", 0);
@@ -894,8 +900,8 @@ static void write_action(grpc_exec_ctx *exec_ctx, void *gt, grpc_error *error) {
   GPR_TIMER_BEGIN("write_action", 0);
   grpc_endpoint_write(
       exec_ctx, t->ep, &t->outbuf,
-      grpc_closure_init(&t->write_action_end_locked, write_action_end_locked, t,
-                        grpc_combiner_scheduler(t->combiner, false)));
+      GRPC_CLOSURE_INIT(&t->write_action_end_locked, write_action_end_locked, t,
+                        grpc_combiner_scheduler(t->combiner)));
   GPR_TIMER_END("write_action", 0);
 }
 
@@ -929,23 +935,11 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
                       "continue writing [!covered]");
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_closure_run(
-          exec_ctx,
-          grpc_closure_init(
-              &t->write_action_begin_locked, write_action_begin_locked, t,
-              grpc_combiner_finally_scheduler(t->combiner, false)),
-          GRPC_ERROR_NONE);
-      break;
-    case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER:
-      GPR_TIMER_MARK("state=writing_stale_with_poller", 0);
-      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
-                      "continue writing [covered]");
-      GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_closure_run(
+      GRPC_CLOSURE_RUN(
           exec_ctx,
-          grpc_closure_init(&t->write_action_begin_locked,
+          GRPC_CLOSURE_INIT(&t->write_action_begin_locked,
                             write_action_begin_locked, t,
-                            grpc_combiner_finally_scheduler(t->combiner, true)),
+                            grpc_combiner_finally_scheduler(t->combiner)),
           GRPC_ERROR_NONE);
       break;
   }
@@ -956,8 +950,11 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
   GPR_TIMER_END("terminate_writing_with_lock", 0);
 }
 
-static void push_setting(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                         grpc_chttp2_setting_id id, uint32_t value) {
+// Dirties an HTTP2 setting to be sent out next time a writing path occurs.
+// If the change needs to occur immediately, manually initiate a write.
+static void queue_setting_update(grpc_exec_ctx *exec_ctx,
+                                 grpc_chttp2_transport *t,
+                                 grpc_chttp2_setting_id id, uint32_t value) {
   const grpc_chttp2_setting_parameters *sp =
       &grpc_chttp2_settings_parameters[id];
   uint32_t use_value = GPR_CLAMP(value, sp->min_value, sp->max_value);
@@ -968,7 +965,6 @@ static void push_setting(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   if (use_value != t->settings[GRPC_LOCAL_SETTINGS][id]) {
     t->settings[GRPC_LOCAL_SETTINGS][id] = use_value;
     t->dirtied_local_settings = 1;
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "push_setting");
   }
 }
 
@@ -1071,7 +1067,7 @@ static void null_then_run_closure(grpc_exec_ctx *exec_ctx,
                                   grpc_closure **closure, grpc_error *error) {
   grpc_closure *c = *closure;
   *closure = NULL;
-  grpc_closure_run(exec_ctx, c, error);
+  GRPC_CLOSURE_RUN(exec_ctx, c, error);
 }
 
 void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
@@ -1113,7 +1109,7 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
     }
     if ((t->write_state == GRPC_CHTTP2_WRITE_STATE_IDLE) ||
         !(closure->next_data.scratch & CLOSURE_BARRIER_MAY_COVER_WRITE)) {
-      grpc_closure_run(exec_ctx, closure, closure->error_data.error);
+      GRPC_CLOSURE_RUN(exec_ctx, closure, closure->error_data.error);
     } else {
       grpc_closure_list_append(&t->run_after_write, closure,
                                closure->error_data.error);
@@ -1211,7 +1207,7 @@ static void do_nothing(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {}
 
 static void log_metadata(const grpc_metadata_batch *md_batch, uint32_t id,
                          bool is_client, bool is_initial) {
-  for (grpc_linked_mdelem *md = md_batch->list.head; md != md_batch->list.tail;
+  for (grpc_linked_mdelem *md = md_batch->list.head; md != NULL;
        md = md->next) {
     char *key = grpc_slice_to_c_string(GRPC_MDKEY(md->md));
     char *value = grpc_slice_to_c_string(GRPC_MDVALUE(md->md));
@@ -1249,7 +1245,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
   grpc_closure *on_complete = op->on_complete;
   if (on_complete == NULL) {
     on_complete =
-        grpc_closure_create(do_nothing, NULL, grpc_schedule_on_exec_ctx);
+        GRPC_CLOSURE_CREATE(do_nothing, NULL, grpc_schedule_on_exec_ctx);
   }
 
   /* use final_data as a barrier until enqueue time; the inital counter is
@@ -1362,7 +1358,6 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       s->next_message_end_offset = s->flow_controlled_bytes_written +
                                    (int64_t)s->flow_controlled_buffer.length +
                                    (int64_t)len;
-      s->complete_fetch_covered_by_poller = op->covered_by_poller;
       if (flags & GRPC_WRITE_BUFFER_HINT) {
         s->next_message_end_offset -= t->write_buffer_size;
         s->write_buffering = true;
@@ -1429,6 +1424,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
         op_payload->recv_initial_metadata.recv_initial_metadata_ready;
     s->recv_initial_metadata =
         op_payload->recv_initial_metadata.recv_initial_metadata;
+    s->trailing_metadata_available =
+        op_payload->recv_initial_metadata.trailing_metadata_available;
     grpc_chttp2_maybe_complete_recv_initial_metadata(exec_ctx, t, s);
   }
 
@@ -1474,6 +1471,21 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
   grpc_chttp2_stream *s = (grpc_chttp2_stream *)gs;
 
+  if (!t->is_client) {
+    if (op->send_initial_metadata) {
+      gpr_timespec deadline =
+          op->payload->send_initial_metadata.send_initial_metadata->deadline;
+      GPR_ASSERT(0 ==
+                 gpr_time_cmp(gpr_inf_future(deadline.clock_type), deadline));
+    }
+    if (op->send_trailing_metadata) {
+      gpr_timespec deadline =
+          op->payload->send_trailing_metadata.send_trailing_metadata->deadline;
+      GPR_ASSERT(0 ==
+                 gpr_time_cmp(gpr_inf_future(deadline.clock_type), deadline));
+    }
+  }
+
   if (GRPC_TRACER_ON(grpc_http_trace)) {
     char *str = grpc_transport_stream_op_batch_string(op);
     gpr_log(GPR_DEBUG, "perform_stream_op[s=%p]: %s", s, str);
@@ -1482,11 +1494,10 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 
   op->handler_private.extra_arg = gs;
   GRPC_CHTTP2_STREAM_REF(s, "perform_stream_op");
-  grpc_closure_sched(
+  GRPC_CLOSURE_SCHED(
       exec_ctx,
-      grpc_closure_init(
-          &op->handler_private.closure, perform_stream_op_locked, op,
-          grpc_combiner_scheduler(t->combiner, op->covered_by_poller)),
+      GRPC_CLOSURE_INIT(&op->handler_private.closure, perform_stream_op_locked,
+                        op, grpc_combiner_scheduler(t->combiner)),
       GRPC_ERROR_NONE);
   GPR_TIMER_END("perform_stream_op", 0);
 }
@@ -1499,7 +1510,7 @@ static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     grpc_chttp2_ping_queue *pq = &t->ping_queues[i];
     for (size_t j = 0; j < GRPC_CHTTP2_PCL_COUNT; j++) {
       grpc_closure_list_fail_all(&pq->lists[j], GRPC_ERROR_REF(error));
-      grpc_closure_list_sched(exec_ctx, &pq->lists[j]);
+      GRPC_CLOSURE_LIST_SCHED(exec_ctx, &pq->lists[j]);
     }
   }
   GRPC_ERROR_UNREF(error);
@@ -1513,7 +1524,7 @@ static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                            GRPC_ERROR_NONE);
   if (grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_NEXT], on_ack,
                                GRPC_ERROR_NONE)) {
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "send_ping");
+    grpc_chttp2_initiate_write(exec_ctx, t, "send_ping");
   }
 }
 
@@ -1521,7 +1532,7 @@ static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                        grpc_error *error) {
   grpc_chttp2_transport *t = tp;
   t->ping_state.is_delayed_ping_timer_set = false;
-  grpc_chttp2_initiate_write(exec_ctx, t, false, "retry_send_ping");
+  grpc_chttp2_initiate_write(exec_ctx, t, "retry_send_ping");
 }
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -1534,9 +1545,9 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     gpr_free(from);
     return;
   }
-  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
+  GRPC_CLOSURE_LIST_SCHED(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
   if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "continue_pings");
+    grpc_chttp2_initiate_write(exec_ctx, t, "continue_pings");
   }
 }
 
@@ -1549,7 +1560,7 @@ static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                         &slice, &http_error);
   grpc_chttp2_goaway_append(t->last_new_stream_id, (uint32_t)http_error,
                             grpc_slice_ref_internal(slice), &t->qbuf);
-  grpc_chttp2_initiate_write(exec_ctx, t, false, "goaway_sent");
+  grpc_chttp2_initiate_write(exec_ctx, t, "goaway_sent");
   GRPC_ERROR_UNREF(error);
 }
 
@@ -1575,12 +1586,6 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
   grpc_chttp2_transport *t = op->handler_private.extra_arg;
   grpc_error *close_transport = op->disconnect_with_error;
 
-  if (op->on_connectivity_state_change != NULL) {
-    grpc_connectivity_state_notify_on_state_change(
-        exec_ctx, &t->channel_callback.state_tracker, op->connectivity_state,
-        op->on_connectivity_state_change);
-  }
-
   if (op->goaway_error) {
     send_goaway(exec_ctx, t, op->goaway_error);
   }
@@ -1604,11 +1609,17 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
                      op->send_ping);
   }
 
+  if (op->on_connectivity_state_change != NULL) {
+    grpc_connectivity_state_notify_on_state_change(
+        exec_ctx, &t->channel_callback.state_tracker, op->connectivity_state,
+        op->on_connectivity_state_change);
+  }
+
   if (close_transport != GRPC_ERROR_NONE) {
     close_transport_locked(exec_ctx, t, close_transport);
   }
 
-  grpc_closure_run(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_RUN(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
 
   GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "transport_op");
 }
@@ -1620,11 +1631,11 @@ static void perform_transport_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   gpr_free(msg);
   op->handler_private.extra_arg = gt;
   GRPC_CHTTP2_REF_TRANSPORT(t, "transport_op");
-  grpc_closure_sched(
-      exec_ctx, grpc_closure_init(&op->handler_private.closure,
-                                  perform_transport_op_locked, op,
-                                  grpc_combiner_scheduler(t->combiner, false)),
-      GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx,
+                     GRPC_CLOSURE_INIT(&op->handler_private.closure,
+                                       perform_transport_op_locked, op,
+                                       grpc_combiner_scheduler(t->combiner)),
+                     GRPC_ERROR_NONE);
 }
 
 /*******************************************************************************
@@ -1779,7 +1790,7 @@ void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
       grpc_slice_buffer_add(
           &t->qbuf, grpc_chttp2_rst_stream_create(s->id, (uint32_t)http_error,
                                                   &s->stats.outgoing));
-      grpc_chttp2_initiate_write(exec_ctx, t, false, "rst_stream");
+      grpc_chttp2_initiate_write(exec_ctx, t, "rst_stream");
     }
   }
   if (due_to_error != GRPC_ERROR_NONE && !s->seen_error) {
@@ -2092,7 +2103,7 @@ static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                                               &s->stats.outgoing));
 
   grpc_chttp2_mark_stream_closed(exec_ctx, t, s, 1, 1, error);
-  grpc_chttp2_initiate_write(exec_ctx, t, false, "close_from_api");
+  grpc_chttp2_initiate_write(exec_ctx, t, "close_from_api");
 }
 
 typedef struct {
@@ -2121,15 +2132,8 @@ static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 
 static void update_bdp(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                        double bdp_dbl) {
-  int32_t bdp;
-  const int32_t kMinBDP = 128;
-  if (bdp_dbl <= kMinBDP) {
-    bdp = kMinBDP;
-  } else if (bdp_dbl > INT32_MAX) {
-    bdp = INT32_MAX;
-  } else {
-    bdp = (int32_t)(bdp_dbl);
-  }
+  // initial window size bounded [1,2^31-1], but we set the min to 128.
+  int32_t bdp = GPR_CLAMP((int32_t)bdp_dbl, 128, INT32_MAX);
   int64_t delta =
       (int64_t)bdp -
       (int64_t)t->settings[GRPC_LOCAL_SETTINGS]
@@ -2141,9 +2145,28 @@ static void update_bdp(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     gpr_log(GPR_DEBUG, "%s: update initial window size to %d", t->peer_string,
             (int)bdp);
   }
-  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
-               (uint32_t)bdp);
-  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE, (uint32_t)bdp);
+  queue_setting_update(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+                       (uint32_t)bdp);
+}
+
+static void update_frame(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                         double bw_dbl, double bdp_dbl) {
+  int32_t bdp = (int32_t)GPR_CLAMP(bdp_dbl, 128.0, INT32_MAX);
+  int32_t target = (int32_t)GPR_MAX(bw_dbl / 1000, bdp);
+  // frame size is bounded [2^14,2^24-1]
+  int32_t frame_size = GPR_CLAMP(target, 16384, 16777215);
+  int64_t delta = (int64_t)frame_size -
+                  (int64_t)t->settings[GRPC_LOCAL_SETTINGS]
+                                      [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE];
+  if (delta == 0 || (delta > -frame_size / 10 && delta < frame_size / 10)) {
+    return;
+  }
+  if (GRPC_TRACER_ON(grpc_bdp_estimator_trace)) {
+    gpr_log(GPR_DEBUG, "%s: update max_frame size to %d", t->peer_string,
+            (int)frame_size);
+  }
+  queue_setting_update(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
+                       (uint32_t)frame_size);
 }
 
 static grpc_error *try_http_parsing(grpc_exec_ctx *exec_ctx,
@@ -2262,6 +2285,7 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
       }
 
       int64_t estimate = -1;
+      double bdp_guess = -1;
       if (grpc_bdp_estimator_get_estimate(&t->bdp_estimator, &estimate)) {
         double target = 1 + log2((double)estimate);
         double memory_pressure = grpc_resource_quota_get_memory_pressure(
@@ -2279,9 +2303,15 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
         }
         double log2_bdp_guess =
             grpc_pid_controller_update(&t->pid_controller, bdp_error, dt);
-        update_bdp(exec_ctx, t, pow(2, log2_bdp_guess));
+        bdp_guess = pow(2, log2_bdp_guess);
+        update_bdp(exec_ctx, t, bdp_guess);
         t->last_pid_update = now;
       }
+
+      double bw = -1;
+      if (grpc_bdp_estimator_get_bw(&t->bdp_estimator, &bw)) {
+        update_frame(exec_ctx, t, bw, bdp_guess);
+      }
     }
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keep_reading");
   } else {
@@ -2476,7 +2506,7 @@ static void reset_byte_stream(grpc_exec_ctx *exec_ctx, void *arg,
     grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, s->t, s);
   } else {
     GPR_ASSERT(error != GRPC_ERROR_NONE);
-    grpc_closure_sched(exec_ctx, s->on_next, GRPC_ERROR_REF(error));
+    GRPC_CLOSURE_SCHED(exec_ctx, s->on_next, GRPC_ERROR_REF(error));
     s->on_next = NULL;
     GRPC_ERROR_UNREF(s->byte_stream_error);
     s->byte_stream_error = GRPC_ERROR_NONE;
@@ -2555,9 +2585,9 @@ static void incoming_byte_stream_next_locked(grpc_exec_ctx *exec_ctx,
   if (s->frame_storage.length > 0) {
     grpc_slice_buffer_swap(&s->frame_storage,
                            &s->unprocessed_incoming_frames_buffer);
-    grpc_closure_sched(exec_ctx, bs->next_action.on_complete, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, bs->next_action.on_complete, GRPC_ERROR_NONE);
   } else if (s->byte_stream_error != GRPC_ERROR_NONE) {
-    grpc_closure_sched(exec_ctx, bs->next_action.on_complete,
+    GRPC_CLOSURE_SCHED(exec_ctx, bs->next_action.on_complete,
                        GRPC_ERROR_REF(s->byte_stream_error));
     if (s->data_parser.parsing_frame != NULL) {
       incoming_byte_stream_unref(exec_ctx, s->data_parser.parsing_frame);
@@ -2567,7 +2597,7 @@ static void incoming_byte_stream_next_locked(grpc_exec_ctx *exec_ctx,
     if (bs->remaining_bytes != 0) {
       s->byte_stream_error =
           GRPC_ERROR_CREATE_FROM_STATIC_STRING("Truncated message");
-      grpc_closure_sched(exec_ctx, bs->next_action.on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, bs->next_action.on_complete,
                          GRPC_ERROR_REF(s->byte_stream_error));
       if (s->data_parser.parsing_frame != NULL) {
         incoming_byte_stream_unref(exec_ctx, s->data_parser.parsing_frame);
@@ -2598,11 +2628,11 @@ static bool incoming_byte_stream_next(grpc_exec_ctx *exec_ctx,
     gpr_ref(&bs->refs);
     bs->next_action.max_size_hint = max_size_hint;
     bs->next_action.on_complete = on_complete;
-    grpc_closure_sched(
+    GRPC_CLOSURE_SCHED(
         exec_ctx,
-        grpc_closure_init(
-            &bs->next_action.closure, incoming_byte_stream_next_locked, bs,
-            grpc_combiner_scheduler(bs->transport->combiner, false)),
+        GRPC_CLOSURE_INIT(&bs->next_action.closure,
+                          incoming_byte_stream_next_locked, bs,
+                          grpc_combiner_scheduler(bs->transport->combiner)),
         GRPC_ERROR_NONE);
     GPR_TIMER_END("incoming_byte_stream_next", 0);
     return false;
@@ -2627,7 +2657,7 @@ static grpc_error *incoming_byte_stream_pull(grpc_exec_ctx *exec_ctx,
   } else {
     grpc_error *error =
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Truncated message");
-    grpc_closure_sched(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
+    GRPC_CLOSURE_SCHED(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
     return error;
   }
   GPR_TIMER_END("incoming_byte_stream_pull", 0);
@@ -2656,11 +2686,10 @@ static void incoming_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_BEGIN("incoming_byte_stream_destroy", 0);
   grpc_chttp2_incoming_byte_stream *bs =
       (grpc_chttp2_incoming_byte_stream *)byte_stream;
-  grpc_closure_sched(
-      exec_ctx,
-      grpc_closure_init(
-          &bs->destroy_action, incoming_byte_stream_destroy_locked, bs,
-          grpc_combiner_scheduler(bs->transport->combiner, false)),
+  GRPC_CLOSURE_SCHED(
+      exec_ctx, GRPC_CLOSURE_INIT(
+                    &bs->destroy_action, incoming_byte_stream_destroy_locked,
+                    bs, grpc_combiner_scheduler(bs->transport->combiner)),
       GRPC_ERROR_NONE);
   GPR_TIMER_END("incoming_byte_stream_destroy", 0);
 }
@@ -2671,7 +2700,7 @@ static void incoming_byte_stream_publish_error(
   grpc_chttp2_stream *s = bs->stream;
 
   GPR_ASSERT(error != GRPC_ERROR_NONE);
-  grpc_closure_sched(exec_ctx, s->on_next, GRPC_ERROR_REF(error));
+  GRPC_CLOSURE_SCHED(exec_ctx, s->on_next, GRPC_ERROR_REF(error));
   s->on_next = NULL;
   GRPC_ERROR_UNREF(s->byte_stream_error);
   s->byte_stream_error = GRPC_ERROR_REF(error);
@@ -2688,7 +2717,7 @@ grpc_error *grpc_chttp2_incoming_byte_stream_push(
     grpc_error *error =
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Too many bytes in stream");
 
-    grpc_closure_sched(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
+    GRPC_CLOSURE_SCHED(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
     grpc_slice_unref_internal(exec_ctx, slice);
     return error;
   } else {
@@ -2711,7 +2740,7 @@ grpc_error *grpc_chttp2_incoming_byte_stream_finished(
     }
   }
   if (error != GRPC_ERROR_NONE && reset_on_error) {
-    grpc_closure_sched(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
+    GRPC_CLOSURE_SCHED(exec_ctx, &s->reset_byte_stream, GRPC_ERROR_REF(error));
   }
   incoming_byte_stream_unref(exec_ctx, bs);
   return error;
@@ -2731,6 +2760,7 @@ grpc_chttp2_incoming_byte_stream *grpc_chttp2_incoming_byte_stream_create(
   gpr_ref_init(&incoming_byte_stream->refs, 2);
   incoming_byte_stream->transport = t;
   incoming_byte_stream->stream = s;
+  GRPC_ERROR_UNREF(s->byte_stream_error);
   s->byte_stream_error = GRPC_ERROR_NONE;
   return incoming_byte_stream;
 }
@@ -2945,5 +2975,5 @@ void grpc_chttp2_transport_start_reading(grpc_exec_ctx *exec_ctx,
     grpc_slice_buffer_move_into(read_buffer, &t->read_buffer);
     gpr_free(read_buffer);
   }
-  grpc_closure_sched(exec_ctx, &t->read_action_locked, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx, &t->read_action_locked, GRPC_ERROR_NONE);
 }
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.h b/src/core/ext/transport/chttp2/transport/chttp2_transport.h
index 83b17d1936..0c4e2a91c0 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.h
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -41,6 +26,10 @@
 extern grpc_tracer_flag grpc_http_trace;
 extern grpc_tracer_flag grpc_flowctl_trace;
 
+#ifndef NDEBUG
+extern grpc_tracer_flag grpc_trace_chttp2_refcount;
+#endif
+
 grpc_transport *grpc_create_chttp2_transport(
     grpc_exec_ctx *exec_ctx, const grpc_channel_args *channel_args,
     grpc_endpoint *ep, int is_client);
diff --git a/src/core/ext/transport/chttp2/transport/frame.h b/src/core/ext/transport/chttp2/transport/frame.h
index ffd4d9669b..dba4c004ec 100644
--- a/src/core/ext/transport/chttp2/transport/frame.h
+++ b/src/core/ext/transport/chttp2/transport/frame.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_data.c b/src/core/ext/transport/chttp2/transport/frame_data.c
index 8cb8489794..dead6be77f 100644
--- a/src/core/ext/transport/chttp2/transport/frame_data.c
+++ b/src/core/ext/transport/chttp2/transport/frame_data.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -143,6 +128,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         grpc_slice_unref_internal(exec_ctx, slice);
         return GRPC_ERROR_REF(p->error);
       case GRPC_CHTTP2_DATA_FH_0:
+        s->stats.incoming.framing_bytes++;
         p->frame_type = *cur;
         switch (p->frame_type) {
           case 0:
@@ -174,6 +160,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         }
       /* fallthrough */
       case GRPC_CHTTP2_DATA_FH_1:
+        s->stats.incoming.framing_bytes++;
         p->frame_size = ((uint32_t)*cur) << 24;
         if (++cur == end) {
           p->state = GRPC_CHTTP2_DATA_FH_2;
@@ -182,6 +169,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         }
       /* fallthrough */
       case GRPC_CHTTP2_DATA_FH_2:
+        s->stats.incoming.framing_bytes++;
         p->frame_size |= ((uint32_t)*cur) << 16;
         if (++cur == end) {
           p->state = GRPC_CHTTP2_DATA_FH_3;
@@ -190,6 +178,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         }
       /* fallthrough */
       case GRPC_CHTTP2_DATA_FH_3:
+        s->stats.incoming.framing_bytes++;
         p->frame_size |= ((uint32_t)*cur) << 8;
         if (++cur == end) {
           p->state = GRPC_CHTTP2_DATA_FH_4;
@@ -198,6 +187,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         }
       /* fallthrough */
       case GRPC_CHTTP2_DATA_FH_4:
+        s->stats.incoming.framing_bytes++;
         GPR_ASSERT(stream_out != NULL);
         GPR_ASSERT(p->parsing_frame == NULL);
         p->frame_size |= ((uint32_t)*cur);
@@ -234,6 +224,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
         }
         uint32_t remaining = (uint32_t)(end - cur);
         if (remaining == p->frame_size) {
+          s->stats.incoming.data_bytes += remaining;
           if (GRPC_ERROR_NONE != (error = grpc_chttp2_incoming_byte_stream_push(
                                       exec_ctx, p->parsing_frame,
                                       grpc_slice_sub(slice, (size_t)(cur - beg),
@@ -253,6 +244,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
           grpc_slice_unref_internal(exec_ctx, slice);
           return GRPC_ERROR_NONE;
         } else if (remaining < p->frame_size) {
+          s->stats.incoming.data_bytes += remaining;
           if (GRPC_ERROR_NONE != (error = grpc_chttp2_incoming_byte_stream_push(
                                       exec_ctx, p->parsing_frame,
                                       grpc_slice_sub(slice, (size_t)(cur - beg),
@@ -265,6 +257,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
           return GRPC_ERROR_NONE;
         } else {
           GPR_ASSERT(remaining > p->frame_size);
+          s->stats.incoming.data_bytes += p->frame_size;
           if (GRPC_ERROR_NONE !=
               (grpc_chttp2_incoming_byte_stream_push(
                   exec_ctx, p->parsing_frame,
@@ -301,7 +294,6 @@ grpc_error *grpc_chttp2_data_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
                                           grpc_chttp2_stream *s,
                                           grpc_slice slice, int is_last) {
   /* grpc_error *error = parse_inner_buffer(exec_ctx, p, t, s, slice); */
-  s->stats.incoming.framing_bytes += GRPC_SLICE_LENGTH(slice);
   if (!s->pending_byte_stream) {
     grpc_slice_ref_internal(slice);
     grpc_slice_buffer_add(&s->frame_storage, slice);
@@ -310,7 +302,7 @@ grpc_error *grpc_chttp2_data_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
     GPR_ASSERT(s->frame_storage.length == 0);
     grpc_slice_ref_internal(slice);
     grpc_slice_buffer_add(&s->unprocessed_incoming_frames_buffer, slice);
-    grpc_closure_sched(exec_ctx, s->on_next, GRPC_ERROR_NONE);
+    GRPC_CLOSURE_SCHED(exec_ctx, s->on_next, GRPC_ERROR_NONE);
     s->on_next = NULL;
   } else {
     grpc_slice_ref_internal(slice);
diff --git a/src/core/ext/transport/chttp2/transport/frame_data.h b/src/core/ext/transport/chttp2/transport/frame_data.h
index 9ed4ad0f21..3f1c787847 100644
--- a/src/core/ext/transport/chttp2/transport/frame_data.h
+++ b/src/core/ext/transport/chttp2/transport/frame_data.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_goaway.c b/src/core/ext/transport/chttp2/transport/frame_goaway.c
index 0f1c8b0772..4bce84f21c 100644
--- a/src/core/ext/transport/chttp2/transport/frame_goaway.c
+++ b/src/core/ext/transport/chttp2/transport/frame_goaway.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_goaway.h b/src/core/ext/transport/chttp2/transport/frame_goaway.h
index 21fe819488..abc48f30c6 100644
--- a/src/core/ext/transport/chttp2/transport/frame_goaway.h
+++ b/src/core/ext/transport/chttp2/transport/frame_goaway.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_ping.c b/src/core/ext/transport/chttp2/transport/frame_ping.c
index 4133774986..31673e622d 100644
--- a/src/core/ext/transport/chttp2/transport/frame_ping.c
+++ b/src/core/ext/transport/chttp2/transport/frame_ping.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -130,7 +115,7 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
               t->ping_acks, t->ping_ack_capacity * sizeof(*t->ping_acks));
         }
         t->ping_acks[t->ping_ack_count++] = p->opaque_8bytes;
-        grpc_chttp2_initiate_write(exec_ctx, t, false, "ping response");
+        grpc_chttp2_initiate_write(exec_ctx, t, "ping response");
       }
     }
   }
diff --git a/src/core/ext/transport/chttp2/transport/frame_ping.h b/src/core/ext/transport/chttp2/transport/frame_ping.h
index 01983d2b12..5969ace9bd 100644
--- a/src/core/ext/transport/chttp2/transport/frame_ping.h
+++ b/src/core/ext/transport/chttp2/transport/frame_ping.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
index e0caa50e92..689dc8935c 100644
--- a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
+++ b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -108,7 +93,7 @@ grpc_error *grpc_chttp2_rst_stream_parser_parse(grpc_exec_ctx *exec_ctx,
                       (((uint32_t)p->reason_bytes[2]) << 8) |
                       (((uint32_t)p->reason_bytes[3]));
     grpc_error *error = GRPC_ERROR_NONE;
-    if (reason != GRPC_HTTP2_NO_ERROR || s->header_frames_received < 2) {
+    if (reason != GRPC_HTTP2_NO_ERROR || s->metadata_buffer[1].size == 0) {
       char *message;
       gpr_asprintf(&message, "Received RST_STREAM with error code %d", reason);
       error = grpc_error_set_int(
diff --git a/src/core/ext/transport/chttp2/transport/frame_rst_stream.h b/src/core/ext/transport/chttp2/transport/frame_rst_stream.h
index 779507a617..d088221b52 100644
--- a/src/core/ext/transport/chttp2/transport/frame_rst_stream.h
+++ b/src/core/ext/transport/chttp2/transport/frame_rst_stream.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_settings.c b/src/core/ext/transport/chttp2/transport/frame_settings.c
index dbaafb5929..e3e432a94a 100644
--- a/src/core/ext/transport/chttp2/transport/frame_settings.c
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_settings.h b/src/core/ext/transport/chttp2/transport/frame_settings.h
index 2a85d0dba7..47479d675d 100644
--- a/src/core/ext/transport/chttp2/transport/frame_settings.h
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/frame_window_update.c b/src/core/ext/transport/chttp2/transport/frame_window_update.c
index 8ed72dddca..682be2c89b 100644
--- a/src/core/ext/transport/chttp2/transport/frame_window_update.c
+++ b/src/core/ext/transport/chttp2/transport/frame_window_update.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -124,8 +109,7 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
                                         received_update);
       bool is_zero = t->outgoing_window <= 0;
       if (was_zero && !is_zero) {
-        grpc_chttp2_initiate_write(exec_ctx, t, false,
-                                   "new_global_flow_control");
+        grpc_chttp2_initiate_write(exec_ctx, t, "new_global_flow_control");
       }
     }
   }
diff --git a/src/core/ext/transport/chttp2/transport/frame_window_update.h b/src/core/ext/transport/chttp2/transport/frame_window_update.h
index f75dfb3d87..698da4e351 100644
--- a/src/core/ext/transport/chttp2/transport/frame_window_update.h
+++ b/src/core/ext/transport/chttp2/transport/frame_window_update.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.c b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
index 126e012aac..a0e748e7b1 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -623,15 +608,14 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
 
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_hpack_compressor *c,
+                               grpc_mdelem **extra_headers,
+                               size_t extra_headers_size,
                                grpc_metadata_batch *metadata,
                                const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf) {
-  framer_state st;
-  grpc_linked_mdelem *l;
-  gpr_timespec deadline;
-
   GPR_ASSERT(options->stream_id != 0);
 
+  framer_state st;
   st.seen_regular_header = 0;
   st.stream_id = options->stream_id;
   st.output = outbuf;
@@ -648,11 +632,14 @@ void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
   if (c->advertise_table_size_change != 0) {
     emit_advertise_table_size_change(c, &st);
   }
+  for (size_t i = 0; i < extra_headers_size; ++i) {
+    hpack_enc(exec_ctx, c, *extra_headers[i], &st);
+  }
   grpc_metadata_batch_assert_ok(metadata);
-  for (l = metadata->list.head; l; l = l->next) {
+  for (grpc_linked_mdelem *l = metadata->list.head; l; l = l->next) {
     hpack_enc(exec_ctx, c, l->md, &st);
   }
-  deadline = metadata->deadline;
+  gpr_timespec deadline = metadata->deadline;
   if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) != 0) {
     deadline_enc(exec_ctx, c, deadline, &st);
   }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.h b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
index 6ce3209604..271192f894 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -100,6 +85,8 @@ typedef struct {
 
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_hpack_compressor *c,
+                               grpc_mdelem **extra_headers,
+                               size_t extra_headers_size,
                                grpc_metadata_batch *metadata,
                                const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf);
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.c b/src/core/ext/transport/chttp2/transport/hpack_parser.c
index bb98bc4a79..7f37365558 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -1664,7 +1649,7 @@ static void force_client_rst_stream(grpc_exec_ctx *exec_ctx, void *sp,
     grpc_slice_buffer_add(
         &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_HTTP2_NO_ERROR,
                                                 &s->stats.outgoing));
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "force_rst_stream");
+    grpc_chttp2_initiate_write(exec_ctx, t, "force_rst_stream");
     grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, true, GRPC_ERROR_NONE);
   }
   GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "final_rst");
@@ -1711,10 +1696,10 @@ grpc_error *grpc_chttp2_header_parser_parse(grpc_exec_ctx *exec_ctx,
              however -- it might be that we receive a RST_STREAM following this
              and can avoid the extra write */
           GRPC_CHTTP2_STREAM_REF(s, "final_rst");
-          grpc_closure_sched(
-              exec_ctx, grpc_closure_create(force_client_rst_stream, s,
-                                            grpc_combiner_finally_scheduler(
-                                                t->combiner, false)),
+          GRPC_CLOSURE_SCHED(
+              exec_ctx,
+              GRPC_CLOSURE_CREATE(force_client_rst_stream, s,
+                                  grpc_combiner_finally_scheduler(t->combiner)),
               GRPC_ERROR_NONE);
         }
         grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, false,
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.h b/src/core/ext/transport/chttp2/transport/hpack_parser.h
index a817183eb5..8fbc6a602b 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.c b/src/core/ext/transport/chttp2/transport/hpack_table.c
index 7aaff55339..944d778011 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.h b/src/core/ext/transport/chttp2/transport/hpack_table.h
index 32a0380e00..2cf8f68506 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/http2_settings.c b/src/core/ext/transport/chttp2/transport/http2_settings.c
index d4905107ef..46b7c0c49c 100644
--- a/src/core/ext/transport/chttp2/transport/http2_settings.c
+++ b/src/core/ext/transport/chttp2/transport/http2_settings.c
@@ -1,32 +1,17 @@
 /*
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 /*
diff --git a/src/core/ext/transport/chttp2/transport/http2_settings.h b/src/core/ext/transport/chttp2/transport/http2_settings.h
index 9781cdc989..706dfc3139 100644
--- a/src/core/ext/transport/chttp2/transport/http2_settings.h
+++ b/src/core/ext/transport/chttp2/transport/http2_settings.h
@@ -1,32 +1,17 @@
 /*
- * Copyright 2017, Google Inc.
- * All rights reserved.
+ * Copyright 2017 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 /*
diff --git a/src/core/ext/transport/chttp2/transport/huffsyms.c b/src/core/ext/transport/chttp2/transport/huffsyms.c
index 68b34e4e2d..f28d8cc30a 100644
--- a/src/core/ext/transport/chttp2/transport/huffsyms.c
+++ b/src/core/ext/transport/chttp2/transport/huffsyms.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/huffsyms.h b/src/core/ext/transport/chttp2/transport/huffsyms.h
index fee00954a0..2e2a5dacae 100644
--- a/src/core/ext/transport/chttp2/transport/huffsyms.h
+++ b/src/core/ext/transport/chttp2/transport/huffsyms.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.c b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
index da0a34d32a..cf0a9ca920 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.c
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.h b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
index 288c917e65..a951d8764c 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.h
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index 9eed73cd71..44ea3bdc61 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -48,6 +33,7 @@
 #include "src/core/ext/transport/chttp2/transport/hpack_parser.h"
 #include "src/core/ext/transport/chttp2/transport/incoming_metadata.h"
 #include "src/core/ext/transport/chttp2/transport/stream_map.h"
+#include "src/core/lib/compression/stream_compression.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/timer.h"
@@ -73,7 +59,6 @@ typedef enum {
   GRPC_CHTTP2_WRITE_STATE_IDLE,
   GRPC_CHTTP2_WRITE_STATE_WRITING,
   GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
-  GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER,
 } grpc_chttp2_write_state;
 
 typedef enum {
@@ -83,6 +68,11 @@ typedef enum {
 } grpc_chttp2_ping_type;
 
 typedef enum {
+  GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY,
+  GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT,
+} grpc_chttp2_optimization_target;
+
+typedef enum {
   GRPC_CHTTP2_PCL_INITIATE = 0,
   GRPC_CHTTP2_PCL_NEXT,
   GRPC_CHTTP2_PCL_INFLIGHT,
@@ -245,6 +235,8 @@ struct grpc_chttp2_transport {
   /** should we probe bdp? */
   bool enable_bdp_probe;
 
+  grpc_chttp2_optimization_target opt_target;
+
   /** various lists of streams */
   grpc_chttp2_stream_list lists[STREAM_LIST_COUNT];
 
@@ -458,12 +450,12 @@ struct grpc_chttp2_stream {
   grpc_slice fetching_slice;
   int64_t next_message_end_offset;
   int64_t flow_controlled_bytes_written;
-  bool complete_fetch_covered_by_poller;
   grpc_closure complete_fetch_locked;
   grpc_closure *fetching_send_message_finished;
 
   grpc_metadata_batch *recv_initial_metadata;
   grpc_closure *recv_initial_metadata_ready;
+  bool *trailing_metadata_available;
   grpc_byte_stream **recv_message;
   grpc_closure *recv_message_ready;
   grpc_metadata_batch *recv_trailing_metadata;
@@ -549,8 +541,7 @@ struct grpc_chttp2_stream {
     The actual call chain is documented in the implementation of this function.
     */
 void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t,
-                                bool covered_by_poller, const char *reason);
+                                grpc_chttp2_transport *t, const char *reason);
 
 typedef enum {
   GRPC_CHTTP2_NOTHING_TO_WRITE,
@@ -766,7 +757,7 @@ void grpc_chttp2_mark_stream_closed(grpc_exec_ctx *exec_ctx,
 void grpc_chttp2_start_writing(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_transport *t);
 
-#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+#ifndef NDEBUG
 #define GRPC_CHTTP2_STREAM_REF(stream, reason) \
   grpc_chttp2_stream_ref(stream, reason)
 #define GRPC_CHTTP2_STREAM_UNREF(exec_ctx, stream, reason) \
@@ -782,8 +773,7 @@ void grpc_chttp2_stream_ref(grpc_chttp2_stream *s);
 void grpc_chttp2_stream_unref(grpc_exec_ctx *exec_ctx, grpc_chttp2_stream *s);
 #endif
 
-//#define GRPC_CHTTP2_REFCOUNTING_DEBUG 1
-#ifdef GRPC_CHTTP2_REFCOUNTING_DEBUG
+#ifndef NDEBUG
 #define GRPC_CHTTP2_REF_TRANSPORT(t, r) \
   grpc_chttp2_ref_transport(t, r, __FILE__, __LINE__)
 #define GRPC_CHTTP2_UNREF_TRANSPORT(cl, t, r) \
diff --git a/src/core/ext/transport/chttp2/transport/parsing.c b/src/core/ext/transport/chttp2/transport/parsing.c
index 1a676e2259..3c8b470b4f 100644
--- a/src/core/ext/transport/chttp2/transport/parsing.c
+++ b/src/core/ext/transport/chttp2/transport/parsing.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -433,7 +418,7 @@ static grpc_error *update_incoming_window(grpc_exec_ctx *exec_ctx,
   GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("parse", t, incoming_window,
                                    incoming_frame_size);
   if (t->incoming_window <= target_incoming_window / 2) {
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "flow_control");
+    grpc_chttp2_initiate_write(exec_ctx, t, "flow_control");
   }
 
   return GRPC_ERROR_NONE;
@@ -696,9 +681,19 @@ static grpc_error *init_header_frame_parser(grpc_exec_ctx *exec_ctx,
   t->parser_data = &t->hpack_parser;
   switch (s->header_frames_received) {
     case 0:
-      t->hpack_parser.on_header = on_initial_header;
+      if (t->is_client && t->header_eof) {
+        GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "parsing Trailers-Only"));
+        if (s->trailing_metadata_available != NULL) {
+          *s->trailing_metadata_available = true;
+        }
+        t->hpack_parser.on_header = on_trailing_header;
+      } else {
+        GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "parsing initial_metadata"));
+        t->hpack_parser.on_header = on_initial_header;
+      }
       break;
     case 1:
+      GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "parsing trailing_metadata"));
       t->hpack_parser.on_header = on_trailing_header;
       break;
     case 2:
diff --git a/src/core/ext/transport/chttp2/transport/stream_lists.c b/src/core/ext/transport/chttp2/transport/stream_lists.c
index 078818fb18..1bf5b34510 100644
--- a/src/core/ext/transport/chttp2/transport/stream_lists.c
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/stream_map.c b/src/core/ext/transport/chttp2/transport/stream_map.c
index 5f5a28446d..e2f10bc208 100644
--- a/src/core/ext/transport/chttp2/transport/stream_map.c
+++ b/src/core/ext/transport/chttp2/transport/stream_map.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/stream_map.h b/src/core/ext/transport/chttp2/transport/stream_map.h
index 203f640680..30c50ba32e 100644
--- a/src/core/ext/transport/chttp2/transport/stream_map.h
+++ b/src/core/ext/transport/chttp2/transport/stream_map.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/varint.c b/src/core/ext/transport/chttp2/transport/varint.c
index e434ad3c07..5f93a23a94 100644
--- a/src/core/ext/transport/chttp2/transport/varint.c
+++ b/src/core/ext/transport/chttp2/transport/varint.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/varint.h b/src/core/ext/transport/chttp2/transport/varint.h
index 450e5fd119..5a2b670f06 100644
--- a/src/core/ext/transport/chttp2/transport/varint.h
+++ b/src/core/ext/transport/chttp2/transport/varint.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index 1ab94ca54f..3e16fda6dc 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2015, Google Inc.
- * All rights reserved.
+ * Copyright 2015 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -125,7 +110,7 @@ static void maybe_initiate_ping(grpc_exec_ctx *exec_ctx,
   }
   pq->inflight_id = t->ping_ctr * GRPC_CHTTP2_PING_TYPE_COUNT + ping_type;
   t->ping_ctr++;
-  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INITIATE]);
+  GRPC_CLOSURE_LIST_SCHED(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INITIATE]);
   grpc_closure_list_move(&pq->lists[GRPC_CHTTP2_PCL_NEXT],
                          &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
   grpc_slice_buffer_add(&t->outbuf,
@@ -176,6 +161,20 @@ static uint32_t target_write_size(grpc_chttp2_transport *t) {
   return 1024 * 1024;
 }
 
+// Returns true if initial_metadata contains only default headers.
+//
+// TODO(roth): The fact that we hard-code these particular headers here
+// is fairly ugly.  Need some better way to know which headers are
+// default, maybe via a bit in the static metadata table?
+static bool is_default_initial_metadata(grpc_metadata_batch *initial_metadata) {
+  int num_default_fields =
+      (initial_metadata->idx.named.status != NULL) +
+      (initial_metadata->idx.named.content_type != NULL) +
+      (initial_metadata->idx.named.grpc_encoding != NULL) +
+      (initial_metadata->idx.named.grpc_accept_encoding != NULL);
+  return (size_t)num_default_fields == initial_metadata->list.count;
+}
+
 grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t) {
   grpc_chttp2_stream *s;
@@ -205,8 +204,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
     while (grpc_chttp2_list_pop_stalled_by_transport(t, &s)) {
       if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s) &&
           stream_ref_if_not_destroyed(&s->refcount->refs)) {
-        grpc_chttp2_initiate_write(exec_ctx, t, false,
-                                   "transport.read_flow_control");
+        grpc_chttp2_initiate_write(exec_ctx, t, "transport.read_flow_control");
       }
     }
   }
@@ -233,31 +231,61 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
         t->is_client ? "CLIENT" : "SERVER", s->id, sent_initial_metadata,
         s->send_initial_metadata != NULL, s->announce_window));
 
+    grpc_mdelem *extra_headers_for_trailing_metadata[2];
+    size_t num_extra_headers_for_trailing_metadata = 0;
+
     /* send initial metadata if it's available */
-    if (!sent_initial_metadata && s->send_initial_metadata) {
-      grpc_encode_header_options hopt = {
-          .stream_id = s->id,
-          .is_eof = false,
-          .use_true_binary_metadata =
-              t->settings
-                  [GRPC_PEER_SETTINGS]
-                  [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] != 0,
-          .max_frame_size = t->settings[GRPC_PEER_SETTINGS]
-                                       [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-          .stats = &s->stats.outgoing};
-      grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
-                                s->send_initial_metadata, &hopt, &t->outbuf);
+    if (!sent_initial_metadata && s->send_initial_metadata != NULL) {
+      // We skip this on the server side if there is no custom initial
+      // metadata, there are no messages to send, and we are also sending
+      // trailing metadata.  This results in a Trailers-Only response,
+      // which is required for retries, as per:
+      // https://github.com/grpc/proposal/blob/master/A6-client-retries.md#when-retries-are-valid
+      if (t->is_client || s->fetching_send_message != NULL ||
+          s->flow_controlled_buffer.length != 0 ||
+          s->send_trailing_metadata == NULL ||
+          !is_default_initial_metadata(s->send_initial_metadata)) {
+        grpc_encode_header_options hopt = {
+            .stream_id = s->id,
+            .is_eof = false,
+            .use_true_binary_metadata =
+                t->settings
+                    [GRPC_PEER_SETTINGS]
+                    [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] != 0,
+            .max_frame_size = t->settings[GRPC_PEER_SETTINGS]
+                                         [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+            .stats = &s->stats.outgoing};
+        grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor, NULL, 0,
+                                  s->send_initial_metadata, &hopt, &t->outbuf);
+        now_writing = true;
+        t->ping_state.pings_before_data_required =
+            t->ping_policy.max_pings_without_data;
+        if (!t->is_client) {
+          t->ping_recv_state.last_ping_recv_time =
+              gpr_inf_past(GPR_CLOCK_MONOTONIC);
+          t->ping_recv_state.ping_strikes = 0;
+        }
+      } else {
+        GRPC_CHTTP2_IF_TRACING(
+            gpr_log(GPR_INFO, "not sending initial_metadata (Trailers-Only)"));
+        // When sending Trailers-Only, we need to move the :status and
+        // content-type headers to the trailers.
+        if (s->send_initial_metadata->idx.named.status != NULL) {
+          extra_headers_for_trailing_metadata
+              [num_extra_headers_for_trailing_metadata++] =
+                  &s->send_initial_metadata->idx.named.status->md;
+        }
+        if (s->send_initial_metadata->idx.named.content_type != NULL) {
+          extra_headers_for_trailing_metadata
+              [num_extra_headers_for_trailing_metadata++] =
+                  &s->send_initial_metadata->idx.named.content_type->md;
+        }
+      }
       s->send_initial_metadata = NULL;
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
-      now_writing = true;
-      t->ping_state.pings_before_data_required =
-          t->ping_policy.max_pings_without_data;
-      if (!t->is_client) {
-        t->ping_recv_state.last_ping_recv_time = 0;
-        t->ping_recv_state.ping_strikes = 0;
-      }
     }
+
     /* send any window updates */
     if (s->announce_window > 0) {
       uint32_t announce = s->announce_window;
@@ -332,6 +360,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
       if (s->send_trailing_metadata != NULL &&
           s->fetching_send_message == NULL &&
           s->flow_controlled_buffer.length == 0) {
+        GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "sending trailing_metadata"));
         if (grpc_metadata_batch_is_empty(s->send_trailing_metadata)) {
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, 0, true,
                                   &s->stats.outgoing, &t->outbuf);
@@ -349,6 +378,8 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                              [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
               .stats = &s->stats.outgoing};
           grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
+                                    extra_headers_for_trailing_metadata,
+                                    num_extra_headers_for_trailing_metadata,
                                     s->send_trailing_metadata, &hopt,
                                     &t->outbuf);
         }
diff --git a/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c b/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
index b6e9e845df..83365192e3 100644
--- a/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
+++ b/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/cronet/transport/cronet_api_dummy.c b/src/core/ext/transport/cronet/transport/cronet_api_dummy.c
index 0dc6a5152f..4f248ad919 100644
--- a/src/core/ext/transport/cronet/transport/cronet_api_dummy.c
+++ b/src/core/ext/transport/cronet/transport/cronet_api_dummy.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.c b/src/core/ext/transport/cronet/transport/cronet_transport.c
index 67974b0b6a..29dfa885de 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.c
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.c
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -781,20 +766,50 @@ static bool op_can_be_run(grpc_transport_stream_op_batch *curr_op,
   bool is_canceled_or_failed = stream_state->state_op_done[OP_CANCEL_ERROR] ||
                                stream_state->state_callback_received[OP_FAILED];
   if (is_canceled_or_failed) {
-    if (op_id == OP_SEND_INITIAL_METADATA) result = false;
-    if (op_id == OP_SEND_MESSAGE) result = false;
-    if (op_id == OP_SEND_TRAILING_METADATA) result = false;
-    if (op_id == OP_CANCEL_ERROR) result = false;
+    if (op_id == OP_SEND_INITIAL_METADATA) {
+      CRONET_LOG(GPR_DEBUG, "Because");
+      result = false;
+    }
+    if (op_id == OP_SEND_MESSAGE) {
+      CRONET_LOG(GPR_DEBUG, "Because");
+      result = false;
+    }
+    if (op_id == OP_SEND_TRAILING_METADATA) {
+      CRONET_LOG(GPR_DEBUG, "Because");
+      result = false;
+    }
+    if (op_id == OP_CANCEL_ERROR) {
+      CRONET_LOG(GPR_DEBUG, "Because");
+      result = false;
+    }
     /* already executed */
     if (op_id == OP_RECV_INITIAL_METADATA &&
-        stream_state->state_op_done[OP_RECV_INITIAL_METADATA])
+        stream_state->state_op_done[OP_RECV_INITIAL_METADATA]) {
+      CRONET_LOG(GPR_DEBUG, "Because");
       result = false;
-    if (op_id == OP_RECV_MESSAGE &&
-        stream_state->state_op_done[OP_RECV_MESSAGE])
+    }
+    if (op_id == OP_RECV_MESSAGE && op_state->state_op_done[OP_RECV_MESSAGE]) {
+      CRONET_LOG(GPR_DEBUG, "Because");
       result = false;
+    }
     if (op_id == OP_RECV_TRAILING_METADATA &&
-        stream_state->state_op_done[OP_RECV_TRAILING_METADATA])
+        stream_state->state_op_done[OP_RECV_TRAILING_METADATA]) {
+      CRONET_LOG(GPR_DEBUG, "Because");
       result = false;
+    }
+    /* ON_COMPLETE can be processed if one of the following conditions is met:
+     * 1. the stream failed
+     * 2. the stream is cancelled, and the callback is received
+     * 3. the stream succeeded before cancel is effective
+     * 4. the stream is cancelled, and the stream is never started */
+    if (op_id == OP_ON_COMPLETE &&
+        !(stream_state->state_callback_received[OP_FAILED] ||
+          stream_state->state_callback_received[OP_CANCELED] ||
+          stream_state->state_callback_received[OP_SUCCEEDED] ||
+          !stream_state->state_op_done[OP_SEND_INITIAL_METADATA])) {
+      CRONET_LOG(GPR_DEBUG, "Because");
+      result = false;
+    }
   } else if (op_id == OP_SEND_INITIAL_METADATA) {
     /* already executed */
     if (stream_state->state_op_done[OP_SEND_INITIAL_METADATA]) result = false;
@@ -883,7 +898,7 @@ static bool op_can_be_run(grpc_transport_stream_op_batch *curr_op,
       CRONET_LOG(GPR_DEBUG, "Because");
       result = false;
     } else if (curr_op->recv_message &&
-               !stream_state->state_op_done[OP_RECV_MESSAGE]) {
+               !op_state->state_op_done[OP_RECV_MESSAGE]) {
       CRONET_LOG(GPR_DEBUG, "Because");
       result = false;
     } else if (curr_op->cancel_stream &&
@@ -1048,17 +1063,17 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
                            OP_RECV_INITIAL_METADATA)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_RECV_INITIAL_METADATA", oas);
     if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
           stream_op->payload->recv_initial_metadata.recv_initial_metadata_ready,
           GRPC_ERROR_NONE);
     } else if (stream_state->state_callback_received[OP_FAILED]) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
           stream_op->payload->recv_initial_metadata.recv_initial_metadata_ready,
           GRPC_ERROR_NONE);
     } else if (stream_state->state_op_done[OP_RECV_TRAILING_METADATA]) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
           stream_op->payload->recv_initial_metadata.recv_initial_metadata_ready,
           GRPC_ERROR_NONE);
@@ -1066,7 +1081,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       grpc_chttp2_incoming_metadata_buffer_publish(
           exec_ctx, &oas->s->state.rs.initial_metadata,
           stream_op->payload->recv_initial_metadata.recv_initial_metadata);
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
           stream_op->payload->recv_initial_metadata.recv_initial_metadata_ready,
           GRPC_ERROR_NONE);
@@ -1078,22 +1093,24 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_RECV_MESSAGE", oas);
     if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
       CRONET_LOG(GPR_DEBUG, "Stream is cancelled.");
-      grpc_closure_sched(exec_ctx,
+      GRPC_CLOSURE_SCHED(exec_ctx,
                          stream_op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
+      oas->state.state_op_done[OP_RECV_MESSAGE] = true;
       result = ACTION_TAKEN_NO_CALLBACK;
     } else if (stream_state->state_callback_received[OP_FAILED]) {
       CRONET_LOG(GPR_DEBUG, "Stream failed.");
-      grpc_closure_sched(exec_ctx,
+      GRPC_CLOSURE_SCHED(exec_ctx,
                          stream_op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
+      oas->state.state_op_done[OP_RECV_MESSAGE] = true;
       result = ACTION_TAKEN_NO_CALLBACK;
     } else if (stream_state->rs.read_stream_closed == true) {
       /* No more data will be received */
       CRONET_LOG(GPR_DEBUG, "read stream closed");
-      grpc_closure_sched(exec_ctx,
+      GRPC_CLOSURE_SCHED(exec_ctx,
                          stream_op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
@@ -1101,7 +1118,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       result = ACTION_TAKEN_NO_CALLBACK;
     } else if (stream_state->flush_read) {
       CRONET_LOG(GPR_DEBUG, "flush read");
-      grpc_closure_sched(exec_ctx,
+      GRPC_CLOSURE_SCHED(exec_ctx,
                          stream_op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
@@ -1142,7 +1159,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
           *((grpc_byte_buffer **)
                 stream_op->payload->recv_message.recv_message) =
               (grpc_byte_buffer *)&stream_state->rs.sbs;
-          grpc_closure_sched(
+          GRPC_CLOSURE_SCHED(
               exec_ctx, stream_op->payload->recv_message.recv_message_ready,
               GRPC_ERROR_NONE);
           stream_state->state_op_done[OP_RECV_MESSAGE] = true;
@@ -1196,7 +1213,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       }
       *((grpc_byte_buffer **)stream_op->payload->recv_message.recv_message) =
           (grpc_byte_buffer *)&stream_state->rs.sbs;
-      grpc_closure_sched(exec_ctx,
+      GRPC_CLOSURE_SCHED(exec_ctx,
                          stream_op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
@@ -1229,8 +1246,8 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
   } else if (stream_op->cancel_stream &&
              op_can_be_run(stream_op, s, &oas->state, OP_CANCEL_ERROR)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_CANCEL_ERROR", oas);
-    CRONET_LOG(GPR_DEBUG, "W: bidirectional_stream_cancel(%p)", s->cbs);
     if (s->cbs) {
+      CRONET_LOG(GPR_DEBUG, "W: bidirectional_stream_cancel(%p)", s->cbs);
       bidirectional_stream_cancel(s->cbs);
       result = ACTION_TAKEN_WITH_CALLBACK;
     } else {
@@ -1245,17 +1262,17 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
              op_can_be_run(stream_op, s, &oas->state, OP_ON_COMPLETE)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_ON_COMPLETE", oas);
     if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
-      grpc_closure_sched(exec_ctx, stream_op->on_complete,
+      GRPC_CLOSURE_SCHED(exec_ctx, stream_op->on_complete,
                          GRPC_ERROR_REF(stream_state->cancel_error));
     } else if (stream_state->state_callback_received[OP_FAILED]) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx, stream_op->on_complete,
           make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable."));
     } else {
       /* All actions in this stream_op are complete. Call the on_complete
        * callback
        */
-      grpc_closure_sched(exec_ctx, stream_op->on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(exec_ctx, stream_op->on_complete, GRPC_ERROR_NONE);
     }
     oas->state.state_op_done[OP_ON_COMPLETE] = true;
     oas->done = true;
@@ -1327,16 +1344,16 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
     /* Cronet does not support :authority header field. We cancel the call when
      this field is present in metadata */
     if (op->recv_initial_metadata) {
-      grpc_closure_sched(
+      GRPC_CLOSURE_SCHED(
           exec_ctx,
           op->payload->recv_initial_metadata.recv_initial_metadata_ready,
           GRPC_ERROR_CANCELLED);
     }
     if (op->recv_message) {
-      grpc_closure_sched(exec_ctx, op->payload->recv_message.recv_message_ready,
+      GRPC_CLOSURE_SCHED(exec_ctx, op->payload->recv_message.recv_message_ready,
                          GRPC_ERROR_CANCELLED);
     }
-    grpc_closure_sched(exec_ctx, op->on_complete, GRPC_ERROR_CANCELLED);
+    GRPC_CLOSURE_SCHED(exec_ctx, op->on_complete, GRPC_ERROR_CANCELLED);
     return;
   }
   stream_obj *s = (stream_obj *)gs;
@@ -1350,7 +1367,7 @@ static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   stream_obj *s = (stream_obj *)gs;
   null_and_maybe_free_read_buffer(s);
   GRPC_ERROR_UNREF(s->state.cancel_error);
-  grpc_closure_sched(exec_ctx, then_schedule_closure, GRPC_ERROR_NONE);
+  GRPC_CLOSURE_SCHED(exec_ctx, then_schedule_closure, GRPC_ERROR_NONE);
 }
 
 static void destroy_transport(grpc_exec_ctx *exec_ctx, grpc_transport *gt) {}
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.h b/src/core/ext/transport/cronet/transport/cronet_transport.h
index 169ce31fd7..3bd4249b79 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.h
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.h
@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2016, Google Inc.
- * All rights reserved.
+ * Copyright 2016 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
diff --git a/src/core/ext/transport/inproc/inproc_plugin.c b/src/core/ext/transport/inproc/inproc_plugin.c
new file mode 100644
index 0000000000..6a796a0b19
--- /dev/null
+++ b/src/core/ext/transport/inproc/inproc_plugin.c
@@ -0,0 +1,29 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/ext/transport/inproc/inproc_transport.h"
+#include "src/core/lib/debug/trace.h"
+
+grpc_tracer_flag grpc_inproc_trace = GRPC_TRACER_INITIALIZER(false, "inproc");
+
+void grpc_inproc_plugin_init(void) {
+  grpc_register_tracer(&grpc_inproc_trace);
+  grpc_inproc_transport_init();
+}
+
+void grpc_inproc_plugin_shutdown(void) { grpc_inproc_transport_shutdown(); }
diff --git a/src/core/ext/transport/inproc/inproc_transport.c b/src/core/ext/transport/inproc/inproc_transport.c
new file mode 100644
index 0000000000..4df64d81e2
--- /dev/null
+++ b/src/core/ext/transport/inproc/inproc_transport.c
@@ -0,0 +1,1277 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/ext/transport/inproc/inproc_transport.h"
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+#include <string.h>
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/surface/api_trace.h"
+#include "src/core/lib/surface/channel.h"
+#include "src/core/lib/surface/channel_stack_type.h"
+#include "src/core/lib/surface/server.h"
+#include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/lib/transport/error_utils.h"
+#include "src/core/lib/transport/transport_impl.h"
+
+#define INPROC_LOG(...)                                          \
+  do {                                                           \
+    if (GRPC_TRACER_ON(grpc_inproc_trace)) gpr_log(__VA_ARGS__); \
+  } while (0)
+
+static const grpc_transport_vtable inproc_vtable;
+static grpc_slice g_empty_slice;
+static grpc_slice g_fake_path_key;
+static grpc_slice g_fake_path_value;
+static grpc_slice g_fake_auth_key;
+static grpc_slice g_fake_auth_value;
+
+typedef struct {
+  gpr_mu mu;
+  gpr_refcount refs;
+} shared_mu;
+
+typedef struct inproc_transport {
+  grpc_transport base;
+  shared_mu *mu;
+  gpr_refcount refs;
+  bool is_client;
+  grpc_connectivity_state_tracker connectivity;
+  void (*accept_stream_cb)(grpc_exec_ctx *exec_ctx, void *user_data,
+                           grpc_transport *transport, const void *server_data);
+  void *accept_stream_data;
+  bool is_closed;
+  struct inproc_transport *other_side;
+  struct inproc_stream *stream_list;
+} inproc_transport;
+
+typedef struct sb_list_entry {
+  grpc_slice_buffer sb;
+  struct sb_list_entry *next;
+} sb_list_entry;
+
+// Specialize grpc_byte_stream for our use case
+typedef struct {
+  grpc_byte_stream base;
+  sb_list_entry *le;
+} inproc_slice_byte_stream;
+
+typedef struct {
+  // TODO (vjpai): Add some inlined elements to avoid alloc in simple cases
+  sb_list_entry *head;
+  sb_list_entry *tail;
+} slice_buffer_list;
+
+static void slice_buffer_list_init(slice_buffer_list *l) {
+  l->head = NULL;
+  l->tail = NULL;
+}
+
+static void sb_list_entry_destroy(grpc_exec_ctx *exec_ctx, sb_list_entry *le) {
+  grpc_slice_buffer_destroy_internal(exec_ctx, &le->sb);
+  gpr_free(le);
+}
+
+static void slice_buffer_list_destroy(grpc_exec_ctx *exec_ctx,
+                                      slice_buffer_list *l) {
+  sb_list_entry *curr = l->head;
+  while (curr != NULL) {
+    sb_list_entry *le = curr;
+    curr = curr->next;
+    sb_list_entry_destroy(exec_ctx, le);
+  }
+  l->head = NULL;
+  l->tail = NULL;
+}
+
+static bool slice_buffer_list_empty(slice_buffer_list *l) {
+  return l->head == NULL;
+}
+
+static void slice_buffer_list_append_entry(slice_buffer_list *l,
+                                           sb_list_entry *next) {
+  next->next = NULL;
+  if (l->tail) {
+    l->tail->next = next;
+    l->tail = next;
+  } else {
+    l->head = next;
+    l->tail = next;
+  }
+}
+
+static grpc_slice_buffer *slice_buffer_list_append(slice_buffer_list *l) {
+  sb_list_entry *next = gpr_malloc(sizeof(*next));
+  grpc_slice_buffer_init(&next->sb);
+  slice_buffer_list_append_entry(l, next);
+  return &next->sb;
+}
+
+static sb_list_entry *slice_buffer_list_pophead(slice_buffer_list *l) {
+  sb_list_entry *ret = l->head;
+  l->head = l->head->next;
+  if (l->head == NULL) {
+    l->tail = NULL;
+  }
+  return ret;
+}
+
+typedef struct inproc_stream {
+  inproc_transport *t;
+  grpc_metadata_batch to_read_initial_md;
+  uint32_t to_read_initial_md_flags;
+  bool to_read_initial_md_filled;
+  slice_buffer_list to_read_message;
+  grpc_metadata_batch to_read_trailing_md;
+  bool to_read_trailing_md_filled;
+  bool reads_needed;
+  bool read_closure_scheduled;
+  grpc_closure read_closure;
+  // Write buffer used only during gap at init time when client-side
+  // stream is set up but server side stream is not yet set up
+  grpc_metadata_batch write_buffer_initial_md;
+  bool write_buffer_initial_md_filled;
+  uint32_t write_buffer_initial_md_flags;
+  gpr_timespec write_buffer_deadline;
+  slice_buffer_list write_buffer_message;
+  grpc_metadata_batch write_buffer_trailing_md;
+  bool write_buffer_trailing_md_filled;
+  grpc_error *write_buffer_cancel_error;
+
+  struct inproc_stream *other_side;
+  bool other_side_closed;               // won't talk anymore
+  bool write_buffer_other_side_closed;  // on hold
+  grpc_stream_refcount *refs;
+  grpc_closure *closure_at_destroy;
+
+  gpr_arena *arena;
+
+  grpc_transport_stream_op_batch *recv_initial_md_op;
+  grpc_transport_stream_op_batch *recv_message_op;
+  grpc_transport_stream_op_batch *recv_trailing_md_op;
+
+  inproc_slice_byte_stream recv_message_stream;
+
+  bool initial_md_sent;
+  bool trailing_md_sent;
+  bool initial_md_recvd;
+  bool trailing_md_recvd;
+
+  bool closed;
+
+  grpc_error *cancel_self_error;
+  grpc_error *cancel_other_error;
+
+  gpr_timespec deadline;
+
+  bool listed;
+  struct inproc_stream *stream_list_prev;
+  struct inproc_stream *stream_list_next;
+} inproc_stream;
+
+static bool inproc_slice_byte_stream_next(grpc_exec_ctx *exec_ctx,
+                                          grpc_byte_stream *bs, size_t max,
+                                          grpc_closure *on_complete) {
+  inproc_slice_byte_stream *stream = (inproc_slice_byte_stream *)bs;
+  return (stream->le->sb.count != 0);
+}
+
+static grpc_error *inproc_slice_byte_stream_pull(grpc_exec_ctx *exec_ctx,
+                                                 grpc_byte_stream *bs,
+                                                 grpc_slice *slice) {
+  inproc_slice_byte_stream *stream = (inproc_slice_byte_stream *)bs;
+  *slice = grpc_slice_buffer_take_first(&stream->le->sb);
+  return GRPC_ERROR_NONE;
+}
+
+static void inproc_slice_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
+                                             grpc_byte_stream *bs) {
+  inproc_slice_byte_stream *stream = (inproc_slice_byte_stream *)bs;
+  sb_list_entry_destroy(exec_ctx, stream->le);
+}
+
+void inproc_slice_byte_stream_init(inproc_slice_byte_stream *s,
+                                   sb_list_entry *le) {
+  s->base.length = (uint32_t)le->sb.length;
+  s->base.flags = 0;
+  s->base.next = inproc_slice_byte_stream_next;
+  s->base.pull = inproc_slice_byte_stream_pull;
+  s->base.destroy = inproc_slice_byte_stream_destroy;
+  s->le = le;
+}
+
+static void ref_transport(inproc_transport *t) {
+  INPROC_LOG(GPR_DEBUG, "ref_transport %p", t);
+  gpr_ref(&t->refs);
+}
+
+static void really_destroy_transport(grpc_exec_ctx *exec_ctx,
+                                     inproc_transport *t) {
+  INPROC_LOG(GPR_DEBUG, "really_destroy_transport %p", t);
+  grpc_connectivity_state_destroy(exec_ctx, &t->connectivity);
+  if (gpr_unref(&t->mu->refs)) {
+    gpr_free(t->mu);
+  }
+  gpr_free(t);
+}
+
+static void unref_transport(grpc_exec_ctx *exec_ctx, inproc_transport *t) {
+  INPROC_LOG(GPR_DEBUG, "unref_transport %p", t);
+  if (gpr_unref(&t->refs)) {
+    really_destroy_transport(exec_ctx, t);
+  }
+}
+
+#ifndef NDEBUG
+#define STREAM_REF(refs, reason) grpc_stream_ref(refs, reason)
+#define STREAM_UNREF(e, refs, reason) grpc_stream_unref(e, refs, reason)
+#else
+#define STREAM_REF(refs, reason) grpc_stream_ref(refs)
+#define STREAM_UNREF(e, refs, reason) grpc_stream_unref(e, refs)
+#endif
+
+static void ref_stream(inproc_stream *s, const char *reason) {
+  INPROC_LOG(GPR_DEBUG, "ref_stream %p %s", s, reason);
+  STREAM_REF(s->refs, reason);
+}
+
+static void unref_stream(grpc_exec_ctx *exec_ctx, inproc_stream *s,
+                         const char *reason) {
+  INPROC_LOG(GPR_DEBUG, "unref_stream %p %s", s, reason);
+  STREAM_UNREF(exec_ctx, s->refs, reason);
+}
+
+static void really_destroy_stream(grpc_exec_ctx *exec_ctx, inproc_stream *s) {
+  INPROC_LOG(GPR_DEBUG, "really_destroy_stream %p", s);
+
+  slice_buffer_list_destroy(exec_ctx, &s->to_read_message);
+  slice_buffer_list_destroy(exec_ctx, &s->write_buffer_message);
+  GRPC_ERROR_UNREF(s->write_buffer_cancel_error);
+  GRPC_ERROR_UNREF(s->cancel_self_error);
+  GRPC_ERROR_UNREF(s->cancel_other_error);
+
+  unref_transport(exec_ctx, s->t);
+
+  if (s->closure_at_destroy) {
+    GRPC_CLOSURE_SCHED(exec_ctx, s->closure_at_destroy, GRPC_ERROR_NONE);
+  }
+}
+
+static void read_state_machine(grpc_exec_ctx *exec_ctx, void *arg,
+                               grpc_error *error);
+
+static void log_metadata(const grpc_metadata_batch *md_batch, bool is_client,
+                         bool is_initial) {
+  for (grpc_linked_mdelem *md = md_batch->list.head; md != NULL;
+       md = md->next) {
+    char *key = grpc_slice_to_c_string(GRPC_MDKEY(md->md));
+    char *value = grpc_slice_to_c_string(GRPC_MDVALUE(md->md));
+    gpr_log(GPR_INFO, "INPROC:%s:%s: %s: %s", is_initial ? "HDR" : "TRL",
+            is_client ? "CLI" : "SVR", key, value);
+    gpr_free(key);
+    gpr_free(value);
+  }
+}
+
+static grpc_error *fill_in_metadata(grpc_exec_ctx *exec_ctx, inproc_stream *s,
+                                    const grpc_metadata_batch *metadata,
+                                    uint32_t flags, grpc_metadata_batch *out_md,
+                                    uint32_t *outflags, bool *markfilled) {
+  if (GRPC_TRACER_ON(grpc_inproc_trace)) {
+    log_metadata(metadata, s->t->is_client, outflags != NULL);
+  }
+
+  if (outflags != NULL) {
+    *outflags = flags;
+  }
+  if (markfilled != NULL) {
+    *markfilled = true;
+  }
+  grpc_error *error = GRPC_ERROR_NONE;
+  for (grpc_linked_mdelem *elem = metadata->list.head;
+       (elem != NULL) && (error == GRPC_ERROR_NONE); elem = elem->next) {
+    grpc_linked_mdelem *nelem = gpr_arena_alloc(s->arena, sizeof(*nelem));
+    nelem->md = grpc_mdelem_from_slices(
+        exec_ctx, grpc_slice_intern(GRPC_MDKEY(elem->md)),
+        grpc_slice_intern(GRPC_MDVALUE(elem->md)));
+
+    error = grpc_metadata_batch_link_tail(exec_ctx, out_md, nelem);
+  }
+  return error;
+}
+
+static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                       grpc_stream *gs, grpc_stream_refcount *refcount,
+                       const void *server_data, gpr_arena *arena) {
+  INPROC_LOG(GPR_DEBUG, "init_stream %p %p %p", gt, gs, server_data);
+  inproc_transport *t = (inproc_transport *)gt;
+  inproc_stream *s = (inproc_stream *)gs;
+  s->arena = arena;
+
+  s->refs = refcount;
+  // Ref this stream right now
+  ref_stream(s, "inproc_init_stream:init");
+
+  grpc_metadata_batch_init(&s->to_read_initial_md);
+  s->to_read_initial_md_flags = 0;
+  s->to_read_initial_md_filled = false;
+  grpc_metadata_batch_init(&s->to_read_trailing_md);
+  s->to_read_trailing_md_filled = false;
+  grpc_metadata_batch_init(&s->write_buffer_initial_md);
+  s->write_buffer_initial_md_flags = 0;
+  s->write_buffer_initial_md_filled = false;
+  grpc_metadata_batch_init(&s->write_buffer_trailing_md);
+  s->write_buffer_trailing_md_filled = false;
+  slice_buffer_list_init(&s->to_read_message);
+  slice_buffer_list_init(&s->write_buffer_message);
+  s->reads_needed = false;
+  s->read_closure_scheduled = false;
+  GRPC_CLOSURE_INIT(&s->read_closure, read_state_machine, s,
+                    grpc_schedule_on_exec_ctx);
+  s->t = t;
+  s->closure_at_destroy = NULL;
+  s->other_side_closed = false;
+
+  s->initial_md_sent = s->trailing_md_sent = s->initial_md_recvd =
+      s->trailing_md_recvd = false;
+
+  s->closed = false;
+
+  s->cancel_self_error = GRPC_ERROR_NONE;
+  s->cancel_other_error = GRPC_ERROR_NONE;
+  s->write_buffer_cancel_error = GRPC_ERROR_NONE;
+  s->deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+  s->write_buffer_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+
+  s->stream_list_prev = NULL;
+  gpr_mu_lock(&t->mu->mu);
+  s->listed = true;
+  ref_stream(s, "inproc_init_stream:list");
+  s->stream_list_next = t->stream_list;
+  if (t->stream_list) {
+    t->stream_list->stream_list_prev = s;
+  }
+  t->stream_list = s;
+  gpr_mu_unlock(&t->mu->mu);
+
+  if (!server_data) {
+    ref_transport(t);
+    inproc_transport *st = t->other_side;
+    ref_transport(st);
+    s->other_side = NULL;  // will get filled in soon
+    // Pass the client-side stream address to the server-side for a ref
+    ref_stream(s, "inproc_init_stream:clt");  // ref it now on behalf of server
+                                              // side to avoid destruction
+    INPROC_LOG(GPR_DEBUG, "calling accept stream cb %p %p",
+               st->accept_stream_cb, st->accept_stream_data);
+    (*st->accept_stream_cb)(exec_ctx, st->accept_stream_data, &st->base,
+                            (void *)s);
+  } else {
+    // This is the server-side and is being called through accept_stream_cb
+    inproc_stream *cs = (inproc_stream *)server_data;
+    s->other_side = cs;
+    // Ref the server-side stream on behalf of the client now
+    ref_stream(s, "inproc_init_stream:srv");
+
+    // Now we are about to affect the other side, so lock the transport
+    // to make sure that it doesn't get destroyed
+    gpr_mu_lock(&s->t->mu->mu);
+    cs->other_side = s;
+    // Now transfer from the other side's write_buffer if any to the to_read
+    // buffer
+    if (cs->write_buffer_initial_md_filled) {
+      fill_in_metadata(exec_ctx, s, &cs->write_buffer_initial_md,
+                       cs->write_buffer_initial_md_flags,
+                       &s->to_read_initial_md, &s->to_read_initial_md_flags,
+                       &s->to_read_initial_md_filled);
+      s->deadline = gpr_time_min(s->deadline, cs->write_buffer_deadline);
+      grpc_metadata_batch_clear(exec_ctx, &cs->write_buffer_initial_md);
+      cs->write_buffer_initial_md_filled = false;
+    }
+    while (!slice_buffer_list_empty(&cs->write_buffer_message)) {
+      slice_buffer_list_append_entry(
+          &s->to_read_message,
+          slice_buffer_list_pophead(&cs->write_buffer_message));
+    }
+    if (cs->write_buffer_trailing_md_filled) {
+      fill_in_metadata(exec_ctx, s, &cs->write_buffer_trailing_md, 0,
+                       &s->to_read_trailing_md, NULL,
+                       &s->to_read_trailing_md_filled);
+      grpc_metadata_batch_clear(exec_ctx, &cs->write_buffer_trailing_md);
+      cs->write_buffer_trailing_md_filled = false;
+    }
+    if (cs->write_buffer_cancel_error != GRPC_ERROR_NONE) {
+      s->cancel_other_error = cs->write_buffer_cancel_error;
+      cs->write_buffer_cancel_error = GRPC_ERROR_NONE;
+    }
+
+    gpr_mu_unlock(&s->t->mu->mu);
+  }
+  return 0;  // return value is not important
+}
+
+static void close_stream_locked(grpc_exec_ctx *exec_ctx, inproc_stream *s) {
+  if (!s->closed) {
+    // Release the metadata that we would have written out
+    grpc_metadata_batch_destroy(exec_ctx, &s->write_buffer_initial_md);
+    grpc_metadata_batch_destroy(exec_ctx, &s->write_buffer_trailing_md);
+
+    if (s->listed) {
+      inproc_stream *p = s->stream_list_prev;
+      inproc_stream *n = s->stream_list_next;
+      if (p != NULL) {
+        p->stream_list_next = n;
+      } else {
+        s->t->stream_list = n;
+      }
+      if (n != NULL) {
+        n->stream_list_prev = p;
+      }
+      s->listed = false;
+      unref_stream(exec_ctx, s, "close_stream:list");
+    }
+    s->closed = true;
+    unref_stream(exec_ctx, s, "close_stream:closing");
+  }
+}
+
+// This function means that we are done talking/listening to the other side
+static void close_other_side_locked(grpc_exec_ctx *exec_ctx, inproc_stream *s,
+                                    const char *reason) {
+  if (s->other_side != NULL) {
+    // First release the metadata that came from the other side's arena
+    grpc_metadata_batch_destroy(exec_ctx, &s->to_read_initial_md);
+    grpc_metadata_batch_destroy(exec_ctx, &s->to_read_trailing_md);
+
+    unref_stream(exec_ctx, s->other_side, reason);
+    s->other_side_closed = true;
+    s->other_side = NULL;
+  } else if (!s->other_side_closed) {
+    s->write_buffer_other_side_closed = true;
+  }
+}
+
+static void fail_helper_locked(grpc_exec_ctx *exec_ctx, inproc_stream *s,
+                               grpc_error *error) {
+  INPROC_LOG(GPR_DEBUG, "read_state_machine %p fail_helper", s);
+  // If we're failing this side, we need to make sure that
+  // we also send or have already sent trailing metadata
+  if (!s->trailing_md_sent) {
+    // Send trailing md to the other side indicating cancellation
+    s->trailing_md_sent = true;
+
+    grpc_metadata_batch fake_md;
+    grpc_metadata_batch_init(&fake_md);
+
+    inproc_stream *other = s->other_side;
+    grpc_metadata_batch *dest = (other == NULL) ? &s->write_buffer_trailing_md
+                                                : &other->to_read_trailing_md;
+    bool *destfilled = (other == NULL) ? &s->write_buffer_trailing_md_filled
+                                       : &other->to_read_trailing_md_filled;
+    fill_in_metadata(exec_ctx, s, &fake_md, 0, dest, NULL, destfilled);
+    grpc_metadata_batch_destroy(exec_ctx, &fake_md);
+
+    if (other != NULL) {
+      if (other->cancel_other_error == GRPC_ERROR_NONE) {
+        other->cancel_other_error = GRPC_ERROR_REF(error);
+      }
+      if (other->reads_needed) {
+        if (!other->read_closure_scheduled) {
+          GRPC_CLOSURE_SCHED(exec_ctx, &other->read_closure,
+                             GRPC_ERROR_REF(error));
+          other->read_closure_scheduled = true;
+        }
+        other->reads_needed = false;
+      }
+    } else if (s->write_buffer_cancel_error == GRPC_ERROR_NONE) {
+      s->write_buffer_cancel_error = GRPC_ERROR_REF(error);
+    }
+  }
+  if (s->recv_initial_md_op) {
+    grpc_error *err;
+    if (!s->t->is_client) {
+      // If this is a server, provide initial metadata with a path and authority
+      // since it expects that as well as no error yet
+      grpc_metadata_batch fake_md;
+      grpc_metadata_batch_init(&fake_md);
+      grpc_linked_mdelem *path_md = gpr_arena_alloc(s->arena, sizeof(*path_md));
+      path_md->md =
+          grpc_mdelem_from_slices(exec_ctx, g_fake_path_key, g_fake_path_value);
+      GPR_ASSERT(grpc_metadata_batch_link_tail(exec_ctx, &fake_md, path_md) ==
+                 GRPC_ERROR_NONE);
+      grpc_linked_mdelem *auth_md = gpr_arena_alloc(s->arena, sizeof(*auth_md));
+      auth_md->md =
+          grpc_mdelem_from_slices(exec_ctx, g_fake_auth_key, g_fake_auth_value);
+      GPR_ASSERT(grpc_metadata_batch_link_tail(exec_ctx, &fake_md, auth_md) ==
+                 GRPC_ERROR_NONE);
+
+      fill_in_metadata(
+          exec_ctx, s, &fake_md, 0,
+          s->recv_initial_md_op->payload->recv_initial_metadata
+              .recv_initial_metadata,
+          s->recv_initial_md_op->payload->recv_initial_metadata.recv_flags,
+          NULL);
+      grpc_metadata_batch_destroy(exec_ctx, &fake_md);
+      err = GRPC_ERROR_NONE;
+    } else {
+      err = GRPC_ERROR_REF(error);
+    }
+    INPROC_LOG(GPR_DEBUG,
+               "fail_helper %p scheduling initial-metadata-ready %p %p", s,
+               error, err);
+    GRPC_CLOSURE_SCHED(exec_ctx,
+                       s->recv_initial_md_op->payload->recv_initial_metadata
+                           .recv_initial_metadata_ready,
+                       err);
+    // Last use of err so no need to REF and then UNREF it
+
+    if ((s->recv_initial_md_op != s->recv_message_op) &&
+        (s->recv_initial_md_op != s->recv_trailing_md_op)) {
+      INPROC_LOG(GPR_DEBUG,
+                 "fail_helper %p scheduling initial-metadata-on-complete %p",
+                 error, s);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_initial_md_op->on_complete,
+                         GRPC_ERROR_REF(error));
+    }
+    s->recv_initial_md_op = NULL;
+  }
+  if (s->recv_message_op) {
+    INPROC_LOG(GPR_DEBUG, "fail_helper %p scheduling message-ready %p", s,
+               error);
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, s->recv_message_op->payload->recv_message.recv_message_ready,
+        GRPC_ERROR_REF(error));
+    if (s->recv_message_op != s->recv_trailing_md_op) {
+      INPROC_LOG(GPR_DEBUG, "fail_helper %p scheduling message-on-complete %p",
+                 s, error);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_message_op->on_complete,
+                         GRPC_ERROR_REF(error));
+    }
+    s->recv_message_op = NULL;
+  }
+  if (s->recv_trailing_md_op) {
+    INPROC_LOG(GPR_DEBUG,
+               "fail_helper %p scheduling trailing-md-on-complete %p", s,
+               error);
+    GRPC_CLOSURE_SCHED(exec_ctx, s->recv_trailing_md_op->on_complete,
+                       GRPC_ERROR_REF(error));
+    s->recv_trailing_md_op = NULL;
+  }
+  close_other_side_locked(exec_ctx, s, "fail_helper:other_side");
+  close_stream_locked(exec_ctx, s);
+
+  GRPC_ERROR_UNREF(error);
+}
+
+static void read_state_machine(grpc_exec_ctx *exec_ctx, void *arg,
+                               grpc_error *error) {
+  // This function gets called when we have contents in the unprocessed reads
+  // Get what we want based on our ops wanted
+  // Schedule our appropriate closures
+  // and then return to reads_needed state if still needed
+
+  // Since this is a closure directly invoked by the combiner, it should not
+  // unref the error parameter explicitly; the combiner will do that implicitly
+  grpc_error *new_err = GRPC_ERROR_NONE;
+
+  bool needs_close = false;
+
+  INPROC_LOG(GPR_DEBUG, "read_state_machine %p", arg);
+  inproc_stream *s = (inproc_stream *)arg;
+  gpr_mu *mu = &s->t->mu->mu;  // keep aside in case s gets closed
+  gpr_mu_lock(mu);
+  s->read_closure_scheduled = false;
+  // cancellation takes precedence
+  if (s->cancel_self_error != GRPC_ERROR_NONE) {
+    fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(s->cancel_self_error));
+    goto done;
+  } else if (s->cancel_other_error != GRPC_ERROR_NONE) {
+    fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(s->cancel_other_error));
+    goto done;
+  } else if (error != GRPC_ERROR_NONE) {
+    fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(error));
+    goto done;
+  }
+
+  if (s->recv_initial_md_op) {
+    if (!s->to_read_initial_md_filled) {
+      // We entered the state machine on some other kind of read even though
+      // we still haven't satisfied initial md . That's an error.
+      new_err =
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Unexpected frame sequencing");
+      INPROC_LOG(GPR_DEBUG,
+                 "read_state_machine %p scheduling on_complete errors for no "
+                 "initial md %p",
+                 s, new_err);
+      fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(new_err));
+      goto done;
+    } else if (s->initial_md_recvd) {
+      new_err =
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Already recvd initial md");
+      INPROC_LOG(
+          GPR_DEBUG,
+          "read_state_machine %p scheduling on_complete errors for already "
+          "recvd initial md %p",
+          s, new_err);
+      fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(new_err));
+      goto done;
+    }
+
+    s->initial_md_recvd = true;
+    new_err = fill_in_metadata(
+        exec_ctx, s, &s->to_read_initial_md, s->to_read_initial_md_flags,
+        s->recv_initial_md_op->payload->recv_initial_metadata
+            .recv_initial_metadata,
+        s->recv_initial_md_op->payload->recv_initial_metadata.recv_flags, NULL);
+    s->recv_initial_md_op->payload->recv_initial_metadata.recv_initial_metadata
+        ->deadline = s->deadline;
+    grpc_metadata_batch_clear(exec_ctx, &s->to_read_initial_md);
+    s->to_read_initial_md_filled = false;
+    INPROC_LOG(GPR_DEBUG,
+               "read_state_machine %p scheduling initial-metadata-ready %p", s,
+               new_err);
+    GRPC_CLOSURE_SCHED(exec_ctx,
+                       s->recv_initial_md_op->payload->recv_initial_metadata
+                           .recv_initial_metadata_ready,
+                       GRPC_ERROR_REF(new_err));
+    if ((s->recv_initial_md_op != s->recv_message_op) &&
+        (s->recv_initial_md_op != s->recv_trailing_md_op)) {
+      INPROC_LOG(
+          GPR_DEBUG,
+          "read_state_machine %p scheduling initial-metadata-on-complete %p", s,
+          new_err);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_initial_md_op->on_complete,
+                         GRPC_ERROR_REF(new_err));
+    }
+    s->recv_initial_md_op = NULL;
+
+    if (new_err != GRPC_ERROR_NONE) {
+      INPROC_LOG(GPR_DEBUG,
+                 "read_state_machine %p scheduling on_complete errors2 %p", s,
+                 new_err);
+      fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(new_err));
+      goto done;
+    }
+  }
+  if (s->to_read_initial_md_filled) {
+    new_err = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Unexpected recv frame");
+    fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(new_err));
+    goto done;
+  }
+  if (!slice_buffer_list_empty(&s->to_read_message) && s->recv_message_op) {
+    inproc_slice_byte_stream_init(
+        &s->recv_message_stream,
+        slice_buffer_list_pophead(&s->to_read_message));
+    *s->recv_message_op->payload->recv_message.recv_message =
+        &s->recv_message_stream.base;
+    INPROC_LOG(GPR_DEBUG, "read_state_machine %p scheduling message-ready", s);
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, s->recv_message_op->payload->recv_message.recv_message_ready,
+        GRPC_ERROR_NONE);
+    if (s->recv_message_op != s->recv_trailing_md_op) {
+      INPROC_LOG(GPR_DEBUG,
+                 "read_state_machine %p scheduling message-on-complete %p", s,
+                 new_err);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_message_op->on_complete,
+                         GRPC_ERROR_REF(new_err));
+    }
+    s->recv_message_op = NULL;
+  }
+  if (s->to_read_trailing_md_filled) {
+    if (s->trailing_md_recvd) {
+      new_err =
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Already recvd trailing md");
+      INPROC_LOG(
+          GPR_DEBUG,
+          "read_state_machine %p scheduling on_complete errors for already "
+          "recvd trailing md %p",
+          s, new_err);
+      fail_helper_locked(exec_ctx, s, GRPC_ERROR_REF(new_err));
+      goto done;
+    }
+    if (s->recv_message_op != NULL) {
+      // This message needs to be wrapped up because it will never be
+      // satisfied
+      INPROC_LOG(GPR_DEBUG, "read_state_machine %p scheduling message-ready",
+                 s);
+      GRPC_CLOSURE_SCHED(
+          exec_ctx,
+          s->recv_message_op->payload->recv_message.recv_message_ready,
+          GRPC_ERROR_NONE);
+      if (s->recv_message_op != s->recv_trailing_md_op) {
+        INPROC_LOG(GPR_DEBUG,
+                   "read_state_machine %p scheduling message-on-complete %p", s,
+                   new_err);
+        GRPC_CLOSURE_SCHED(exec_ctx, s->recv_message_op->on_complete,
+                           GRPC_ERROR_REF(new_err));
+      }
+      s->recv_message_op = NULL;
+    }
+    if (s->recv_trailing_md_op != NULL) {
+      // We wanted trailing metadata and we got it
+      s->trailing_md_recvd = true;
+      new_err =
+          fill_in_metadata(exec_ctx, s, &s->to_read_trailing_md, 0,
+                           s->recv_trailing_md_op->payload
+                               ->recv_trailing_metadata.recv_trailing_metadata,
+                           NULL, NULL);
+      grpc_metadata_batch_clear(exec_ctx, &s->to_read_trailing_md);
+      s->to_read_trailing_md_filled = false;
+
+      // We should schedule the recv_trailing_md_op completion if
+      // 1. this stream is the client-side
+      // 2. this stream is the server-side AND has already sent its trailing md
+      //    (If the server hasn't already sent its trailing md, it doesn't have
+      //     a final status, so don't mark this op complete)
+      if (s->t->is_client || s->trailing_md_sent) {
+        INPROC_LOG(
+            GPR_DEBUG,
+            "read_state_machine %p scheduling trailing-md-on-complete %p", s,
+            new_err);
+        GRPC_CLOSURE_SCHED(exec_ctx, s->recv_trailing_md_op->on_complete,
+                           GRPC_ERROR_REF(new_err));
+        s->recv_trailing_md_op = NULL;
+        needs_close = true;
+      } else {
+        INPROC_LOG(GPR_DEBUG,
+                   "read_state_machine %p server needs to delay handling "
+                   "trailing-md-on-complete %p",
+                   s, new_err);
+      }
+    } else {
+      INPROC_LOG(
+          GPR_DEBUG,
+          "read_state_machine %p has trailing md but not yet waiting for it",
+          s);
+    }
+  }
+  if (s->trailing_md_recvd && s->recv_message_op) {
+    // No further message will come on this stream, so finish off the
+    // recv_message_op
+    INPROC_LOG(GPR_DEBUG, "read_state_machine %p scheduling message-ready", s);
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, s->recv_message_op->payload->recv_message.recv_message_ready,
+        GRPC_ERROR_NONE);
+    if (s->recv_message_op != s->recv_trailing_md_op) {
+      INPROC_LOG(GPR_DEBUG,
+                 "read_state_machine %p scheduling message-on-complete %p", s,
+                 new_err);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_message_op->on_complete,
+                         GRPC_ERROR_REF(new_err));
+    }
+    s->recv_message_op = NULL;
+  }
+  if (s->recv_message_op || s->recv_trailing_md_op) {
+    // Didn't get the item we wanted so we still need to get
+    // rescheduled
+    INPROC_LOG(GPR_DEBUG, "read_state_machine %p still needs closure %p %p", s,
+               s->recv_message_op, s->recv_trailing_md_op);
+    s->reads_needed = true;
+  }
+done:
+  if (needs_close) {
+    close_other_side_locked(exec_ctx, s, "read_state_machine");
+    close_stream_locked(exec_ctx, s);
+  }
+  gpr_mu_unlock(mu);
+  GRPC_ERROR_UNREF(new_err);
+}
+
+static grpc_closure do_nothing_closure;
+
+static bool cancel_stream_locked(grpc_exec_ctx *exec_ctx, inproc_stream *s,
+                                 grpc_error *error) {
+  bool ret = false;  // was the cancel accepted
+  INPROC_LOG(GPR_DEBUG, "cancel_stream %p with %s", s,
+             grpc_error_string(error));
+  if (s->cancel_self_error == GRPC_ERROR_NONE) {
+    ret = true;
+    s->cancel_self_error = GRPC_ERROR_REF(error);
+    if (s->reads_needed) {
+      if (!s->read_closure_scheduled) {
+        GRPC_CLOSURE_SCHED(exec_ctx, &s->read_closure,
+                           GRPC_ERROR_REF(s->cancel_self_error));
+        s->read_closure_scheduled = true;
+      }
+      s->reads_needed = false;
+    }
+    // Send trailing md to the other side indicating cancellation, even if we
+    // already have
+    s->trailing_md_sent = true;
+
+    grpc_metadata_batch cancel_md;
+    grpc_metadata_batch_init(&cancel_md);
+
+    inproc_stream *other = s->other_side;
+    grpc_metadata_batch *dest = (other == NULL) ? &s->write_buffer_trailing_md
+                                                : &other->to_read_trailing_md;
+    bool *destfilled = (other == NULL) ? &s->write_buffer_trailing_md_filled
+                                       : &other->to_read_trailing_md_filled;
+    fill_in_metadata(exec_ctx, s, &cancel_md, 0, dest, NULL, destfilled);
+    grpc_metadata_batch_destroy(exec_ctx, &cancel_md);
+
+    if (other != NULL) {
+      if (other->cancel_other_error == GRPC_ERROR_NONE) {
+        other->cancel_other_error = GRPC_ERROR_REF(s->cancel_self_error);
+      }
+      if (other->reads_needed) {
+        if (!other->read_closure_scheduled) {
+          GRPC_CLOSURE_SCHED(exec_ctx, &other->read_closure,
+                             GRPC_ERROR_REF(other->cancel_other_error));
+          other->read_closure_scheduled = true;
+        }
+        other->reads_needed = false;
+      }
+    } else if (s->write_buffer_cancel_error == GRPC_ERROR_NONE) {
+      s->write_buffer_cancel_error = GRPC_ERROR_REF(s->cancel_self_error);
+    }
+
+    // if we are a server and already received trailing md but
+    // couldn't complete that because we hadn't yet sent out trailing
+    // md, now's the chance
+    if (!s->t->is_client && s->trailing_md_recvd && s->recv_trailing_md_op) {
+      INPROC_LOG(GPR_DEBUG,
+                 "cancel_stream %p scheduling trailing-md-on-complete %p", s,
+                 s->cancel_self_error);
+      GRPC_CLOSURE_SCHED(exec_ctx, s->recv_trailing_md_op->on_complete,
+                         GRPC_ERROR_REF(s->cancel_self_error));
+      s->recv_trailing_md_op = NULL;
+    }
+  }
+
+  close_other_side_locked(exec_ctx, s, "cancel_stream:other_side");
+  close_stream_locked(exec_ctx, s);
+
+  GRPC_ERROR_UNREF(error);
+  return ret;
+}
+
+static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                              grpc_stream *gs,
+                              grpc_transport_stream_op_batch *op) {
+  INPROC_LOG(GPR_DEBUG, "perform_stream_op %p %p %p", gt, gs, op);
+  inproc_stream *s = (inproc_stream *)gs;
+  gpr_mu *mu = &s->t->mu->mu;  // save aside in case s gets closed
+  gpr_mu_lock(mu);
+
+  if (GRPC_TRACER_ON(grpc_inproc_trace)) {
+    if (op->send_initial_metadata) {
+      log_metadata(op->payload->send_initial_metadata.send_initial_metadata,
+                   s->t->is_client, true);
+    }
+    if (op->send_trailing_metadata) {
+      log_metadata(op->payload->send_trailing_metadata.send_trailing_metadata,
+                   s->t->is_client, false);
+    }
+  }
+  grpc_error *error = GRPC_ERROR_NONE;
+  grpc_closure *on_complete = op->on_complete;
+  if (on_complete == NULL) {
+    on_complete = &do_nothing_closure;
+  }
+
+  if (op->cancel_stream) {
+    // Call cancel_stream_locked without ref'ing the cancel_error because
+    // this function is responsible to make sure that that field gets unref'ed
+    cancel_stream_locked(exec_ctx, s, op->payload->cancel_stream.cancel_error);
+    // this op can complete without an error
+  } else if (s->cancel_self_error != GRPC_ERROR_NONE) {
+    // already self-canceled so still give it an error
+    error = GRPC_ERROR_REF(s->cancel_self_error);
+  } else {
+    INPROC_LOG(GPR_DEBUG, "perform_stream_op %p%s%s%s%s%s%s", s,
+               op->send_initial_metadata ? " send_initial_metadata" : "",
+               op->send_message ? " send_message" : "",
+               op->send_trailing_metadata ? " send_trailing_metadata" : "",
+               op->recv_initial_metadata ? " recv_initial_metadata" : "",
+               op->recv_message ? " recv_message" : "",
+               op->recv_trailing_metadata ? " recv_trailing_metadata" : "");
+  }
+
+  bool needs_close = false;
+
+  if (error == GRPC_ERROR_NONE &&
+      (op->send_initial_metadata || op->send_message ||
+       op->send_trailing_metadata)) {
+    inproc_stream *other = s->other_side;
+    if (s->t->is_closed) {
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Endpoint already shutdown");
+    }
+    if (error == GRPC_ERROR_NONE && op->send_initial_metadata) {
+      grpc_metadata_batch *dest = (other == NULL) ? &s->write_buffer_initial_md
+                                                  : &other->to_read_initial_md;
+      uint32_t *destflags = (other == NULL) ? &s->write_buffer_initial_md_flags
+                                            : &other->to_read_initial_md_flags;
+      bool *destfilled = (other == NULL) ? &s->write_buffer_initial_md_filled
+                                         : &other->to_read_initial_md_filled;
+      if (*destfilled || s->initial_md_sent) {
+        // The buffer is already in use; that's an error!
+        INPROC_LOG(GPR_DEBUG, "Extra initial metadata %p", s);
+        error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Extra initial metadata");
+      } else {
+        if (!other->closed) {
+          fill_in_metadata(
+              exec_ctx, s,
+              op->payload->send_initial_metadata.send_initial_metadata,
+              op->payload->send_initial_metadata.send_initial_metadata_flags,
+              dest, destflags, destfilled);
+        }
+        if (s->t->is_client) {
+          gpr_timespec *dl =
+              (other == NULL) ? &s->write_buffer_deadline : &other->deadline;
+          *dl = gpr_time_min(*dl, op->payload->send_initial_metadata
+                                      .send_initial_metadata->deadline);
+          s->initial_md_sent = true;
+        }
+      }
+    }
+    if (error == GRPC_ERROR_NONE && op->send_message) {
+      size_t remaining = op->payload->send_message.send_message->length;
+      grpc_slice_buffer *dest = slice_buffer_list_append(
+          (other == NULL) ? &s->write_buffer_message : &other->to_read_message);
+      do {
+        grpc_slice message_slice;
+        grpc_closure unused;
+        GPR_ASSERT(grpc_byte_stream_next(exec_ctx,
+                                         op->payload->send_message.send_message,
+                                         SIZE_MAX, &unused));
+        grpc_byte_stream_pull(exec_ctx, op->payload->send_message.send_message,
+                              &message_slice);
+        remaining -= GRPC_SLICE_LENGTH(message_slice);
+        grpc_slice_buffer_add(dest, message_slice);
+      } while (remaining != 0);
+    }
+    if (error == GRPC_ERROR_NONE && op->send_trailing_metadata) {
+      grpc_metadata_batch *dest = (other == NULL) ? &s->write_buffer_trailing_md
+                                                  : &other->to_read_trailing_md;
+      bool *destfilled = (other == NULL) ? &s->write_buffer_trailing_md_filled
+                                         : &other->to_read_trailing_md_filled;
+      if (*destfilled || s->trailing_md_sent) {
+        // The buffer is already in use; that's an error!
+        INPROC_LOG(GPR_DEBUG, "Extra trailing metadata %p", s);
+        error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Extra trailing metadata");
+      } else {
+        if (!other->closed) {
+          fill_in_metadata(
+              exec_ctx, s,
+              op->payload->send_trailing_metadata.send_trailing_metadata, 0,
+              dest, NULL, destfilled);
+        }
+        s->trailing_md_sent = true;
+        if (!s->t->is_client && s->trailing_md_recvd &&
+            s->recv_trailing_md_op) {
+          INPROC_LOG(GPR_DEBUG,
+                     "perform_stream_op %p scheduling trailing-md-on-complete",
+                     s);
+          GRPC_CLOSURE_SCHED(exec_ctx, s->recv_trailing_md_op->on_complete,
+                             GRPC_ERROR_NONE);
+          s->recv_trailing_md_op = NULL;
+          needs_close = true;
+        }
+      }
+    }
+    if (other != NULL && other->reads_needed) {
+      if (!other->read_closure_scheduled) {
+        GRPC_CLOSURE_SCHED(exec_ctx, &other->read_closure, error);
+        other->read_closure_scheduled = true;
+      }
+      other->reads_needed = false;
+    }
+  }
+  if (error == GRPC_ERROR_NONE &&
+      (op->recv_initial_metadata || op->recv_message ||
+       op->recv_trailing_metadata)) {
+    // If there are any reads, mark it so that the read closure will react to
+    // them
+    if (op->recv_initial_metadata) {
+      s->recv_initial_md_op = op;
+    }
+    if (op->recv_message) {
+      s->recv_message_op = op;
+    }
+    if (op->recv_trailing_metadata) {
+      s->recv_trailing_md_op = op;
+    }
+
+    // We want to initiate the closure if:
+    // 1. There is initial metadata and something ready to take that
+    // 2. There is a message and something ready to take it
+    // 3. There is trailing metadata, even if nothing specifically wants
+    //    that because that can shut down the message as well
+    if ((s->to_read_initial_md_filled && op->recv_initial_metadata) ||
+        ((!slice_buffer_list_empty(&s->to_read_message) ||
+          s->trailing_md_recvd) &&
+         op->recv_message) ||
+        (s->to_read_trailing_md_filled)) {
+      if (!s->read_closure_scheduled) {
+        GRPC_CLOSURE_SCHED(exec_ctx, &s->read_closure, GRPC_ERROR_NONE);
+        s->read_closure_scheduled = true;
+      }
+    } else {
+      s->reads_needed = true;
+    }
+  } else {
+    if (error != GRPC_ERROR_NONE) {
+      // Schedule op's read closures that we didn't push to read state machine
+      if (op->recv_initial_metadata) {
+        INPROC_LOG(
+            GPR_DEBUG,
+            "perform_stream_op error %p scheduling initial-metadata-ready %p",
+            s, error);
+        GRPC_CLOSURE_SCHED(
+            exec_ctx,
+            op->payload->recv_initial_metadata.recv_initial_metadata_ready,
+            GRPC_ERROR_REF(error));
+      }
+      if (op->recv_message) {
+        INPROC_LOG(
+            GPR_DEBUG,
+            "perform_stream_op error %p scheduling recv message-ready %p", s,
+            error);
+        GRPC_CLOSURE_SCHED(exec_ctx,
+                           op->payload->recv_message.recv_message_ready,
+                           GRPC_ERROR_REF(error));
+      }
+    }
+    INPROC_LOG(GPR_DEBUG, "perform_stream_op %p scheduling on_complete %p", s,
+               error);
+    GRPC_CLOSURE_SCHED(exec_ctx, on_complete, GRPC_ERROR_REF(error));
+  }
+  if (needs_close) {
+    close_other_side_locked(exec_ctx, s, "perform_stream_op:other_side");
+    close_stream_locked(exec_ctx, s);
+  }
+  gpr_mu_unlock(mu);
+  GRPC_ERROR_UNREF(error);
+}
+
+static void close_transport_locked(grpc_exec_ctx *exec_ctx,
+                                   inproc_transport *t) {
+  INPROC_LOG(GPR_DEBUG, "close_transport %p %d", t, t->is_closed);
+  grpc_connectivity_state_set(
+      exec_ctx, &t->connectivity, GRPC_CHANNEL_SHUTDOWN,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Closing transport."),
+      "close transport");
+  if (!t->is_closed) {
+    t->is_closed = true;
+    /* Also end all streams on this transport */
+    while (t->stream_list != NULL) {
+      // cancel_stream_locked also adjusts stream list
+      cancel_stream_locked(
+          exec_ctx, t->stream_list,
+          grpc_error_set_int(
+              GRPC_ERROR_CREATE_FROM_STATIC_STRING("Transport closed"),
+              GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE));
+    }
+  }
+}
+
+static void perform_transport_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                                 grpc_transport_op *op) {
+  inproc_transport *t = (inproc_transport *)gt;
+  INPROC_LOG(GPR_DEBUG, "perform_transport_op %p %p", t, op);
+  gpr_mu_lock(&t->mu->mu);
+  if (op->on_connectivity_state_change) {
+    grpc_connectivity_state_notify_on_state_change(
+        exec_ctx, &t->connectivity, op->connectivity_state,
+        op->on_connectivity_state_change);
+  }
+  if (op->set_accept_stream) {
+    t->accept_stream_cb = op->set_accept_stream_fn;
+    t->accept_stream_data = op->set_accept_stream_user_data;
+  }
+  if (op->on_consumed) {
+    GRPC_CLOSURE_SCHED(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
+  }
+
+  bool do_close = false;
+  if (op->goaway_error != GRPC_ERROR_NONE) {
+    do_close = true;
+    GRPC_ERROR_UNREF(op->goaway_error);
+  }
+  if (op->disconnect_with_error != GRPC_ERROR_NONE) {
+    do_close = true;
+    GRPC_ERROR_UNREF(op->disconnect_with_error);
+  }
+
+  if (do_close) {
+    close_transport_locked(exec_ctx, t);
+  }
+  gpr_mu_unlock(&t->mu->mu);
+}
+
+static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                           grpc_stream *gs,
+                           grpc_closure *then_schedule_closure) {
+  INPROC_LOG(GPR_DEBUG, "destroy_stream %p %p", gs, then_schedule_closure);
+  inproc_stream *s = (inproc_stream *)gs;
+  s->closure_at_destroy = then_schedule_closure;
+  really_destroy_stream(exec_ctx, s);
+}
+
+static void destroy_transport(grpc_exec_ctx *exec_ctx, grpc_transport *gt) {
+  inproc_transport *t = (inproc_transport *)gt;
+  INPROC_LOG(GPR_DEBUG, "destroy_transport %p", t);
+  gpr_mu_lock(&t->mu->mu);
+  close_transport_locked(exec_ctx, t);
+  gpr_mu_unlock(&t->mu->mu);
+  unref_transport(exec_ctx, t->other_side);
+  unref_transport(exec_ctx, t);
+}
+
+/*******************************************************************************
+ * Main inproc transport functions
+ */
+static void inproc_transports_create(grpc_exec_ctx *exec_ctx,
+                                     grpc_transport **server_transport,
+                                     const grpc_channel_args *server_args,
+                                     grpc_transport **client_transport,
+                                     const grpc_channel_args *client_args) {
+  INPROC_LOG(GPR_DEBUG, "inproc_transports_create");
+  inproc_transport *st = gpr_zalloc(sizeof(*st));
+  inproc_transport *ct = gpr_zalloc(sizeof(*ct));
+  // Share one lock between both sides since both sides get affected
+  st->mu = ct->mu = gpr_malloc(sizeof(*st->mu));
+  gpr_mu_init(&st->mu->mu);
+  gpr_ref_init(&st->mu->refs, 2);
+  st->base.vtable = &inproc_vtable;
+  ct->base.vtable = &inproc_vtable;
+  // Start each side of transport with 2 refs since they each have a ref
+  // to the other
+  gpr_ref_init(&st->refs, 2);
+  gpr_ref_init(&ct->refs, 2);
+  st->is_client = false;
+  ct->is_client = true;
+  grpc_connectivity_state_init(&st->connectivity, GRPC_CHANNEL_READY,
+                               "inproc_server");
+  grpc_connectivity_state_init(&ct->connectivity, GRPC_CHANNEL_READY,
+                               "inproc_client");
+  st->other_side = ct;
+  ct->other_side = st;
+  st->stream_list = NULL;
+  ct->stream_list = NULL;
+  *server_transport = (grpc_transport *)st;
+  *client_transport = (grpc_transport *)ct;
+}
+
+grpc_channel *grpc_inproc_channel_create(grpc_server *server,
+                                         grpc_channel_args *args,
+                                         void *reserved) {
+  GRPC_API_TRACE("grpc_inproc_channel_create(server=%p, args=%p)", 2,
+                 (server, args));
+
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
+  const grpc_channel_args *server_args = grpc_server_get_channel_args(server);
+
+  // Add a default authority channel argument for the client
+
+  grpc_arg default_authority_arg;
+  default_authority_arg.type = GRPC_ARG_STRING;
+  default_authority_arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
+  default_authority_arg.value.string = "inproc.authority";
+  grpc_channel_args *client_args =
+      grpc_channel_args_copy_and_add(args, &default_authority_arg, 1);
+
+  grpc_transport *server_transport;
+  grpc_transport *client_transport;
+  inproc_transports_create(&exec_ctx, &server_transport, server_args,
+                           &client_transport, client_args);
+
+  grpc_server_setup_transport(&exec_ctx, server, server_transport, NULL,
+                              server_args);
+  grpc_channel *channel =
+      grpc_channel_create(&exec_ctx, "inproc", client_args,
+                          GRPC_CLIENT_DIRECT_CHANNEL, client_transport);
+
+  // Free up created channel args
+  grpc_channel_args_destroy(&exec_ctx, client_args);
+
+  // Now finish scheduled operations
+  grpc_exec_ctx_finish(&exec_ctx);
+
+  return channel;
+}
+
+/*******************************************************************************
+ * INTEGRATION GLUE
+ */
+
+static void set_pollset(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                        grpc_stream *gs, grpc_pollset *pollset) {
+  // Nothing to do here
+}
+
+static void set_pollset_set(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
+                            grpc_stream *gs, grpc_pollset_set *pollset_set) {
+  // Nothing to do here
+}
+
+static char *get_peer(grpc_exec_ctx *exec_ctx, grpc_transport *t) {
+  return gpr_strdup("inproc");
+}
+
+static grpc_endpoint *get_endpoint(grpc_exec_ctx *exec_ctx, grpc_transport *t) {
+  return NULL;
+}
+
+static const grpc_transport_vtable inproc_vtable = {
+    sizeof(inproc_stream), "inproc",
+    init_stream,           set_pollset,
+    set_pollset_set,       perform_stream_op,
+    perform_transport_op,  destroy_stream,
+    destroy_transport,     get_peer,
+    get_endpoint};
+
+/*******************************************************************************
+ * GLOBAL INIT AND DESTROY
+ */
+static void do_nothing(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {}
+
+void grpc_inproc_transport_init(void) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  GRPC_CLOSURE_INIT(&do_nothing_closure, do_nothing, NULL,
+                    grpc_schedule_on_exec_ctx);
+  g_empty_slice = grpc_slice_from_static_buffer(NULL, 0);
+
+  grpc_slice key_tmp = grpc_slice_from_static_string(":path");
+  g_fake_path_key = grpc_slice_intern(key_tmp);
+  grpc_slice_unref_internal(&exec_ctx, key_tmp);
+
+  g_fake_path_value = grpc_slice_from_static_string("/");
+
+  grpc_slice auth_tmp = grpc_slice_from_static_string(":authority");
+  g_fake_auth_key = grpc_slice_intern(auth_tmp);
+  grpc_slice_unref_internal(&exec_ctx, auth_tmp);
+
+  g_fake_auth_value = grpc_slice_from_static_string("inproc-fail");
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
+void grpc_inproc_transport_shutdown(void) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_unref_internal(&exec_ctx, g_empty_slice);
+  grpc_slice_unref_internal(&exec_ctx, g_fake_path_key);
+  grpc_slice_unref_internal(&exec_ctx, g_fake_path_value);
+  grpc_slice_unref_internal(&exec_ctx, g_fake_auth_key);
+  grpc_slice_unref_internal(&exec_ctx, g_fake_auth_value);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
diff --git a/src/core/ext/transport/inproc/inproc_transport.h b/src/core/ext/transport/inproc/inproc_transport.h
new file mode 100644
index 0000000000..37e6d99e99
--- /dev/null
+++ b/src/core/ext/transport/inproc/inproc_transport.h
@@ -0,0 +1,41 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_TRANSPORT_INPROC_INPROC_TRANSPORT_H
+#define GRPC_CORE_EXT_TRANSPORT_INPROC_INPROC_TRANSPORT_H
+
+#include "src/core/lib/transport/transport_impl.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+grpc_channel *grpc_inproc_channel_create(grpc_server *server,
+                                         grpc_channel_args *args,
+                                         void *reserved);
+
+extern grpc_tracer_flag grpc_inproc_trace;
+
+void grpc_inproc_transport_init(void);
+void grpc_inproc_transport_shutdown(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_EXT_TRANSPORT_INPROC_INPROC_TRANSPORT_H */