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diff --git a/src/core/lib/client_config/resolver.h b/src/core/lib/client_config/resolver.h
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+++ b/src/core/lib/client_config/resolver.h
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+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * 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.
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_CLIENT_CONFIG_RESOLVER_H
+#define GRPC_CORE_LIB_CLIENT_CONFIG_RESOLVER_H
+
+#include "src/core/lib/client_config/client_config.h"
+#include "src/core/lib/client_config/subchannel.h"
+#include "src/core/lib/iomgr/iomgr.h"
+
+typedef struct grpc_resolver grpc_resolver;
+typedef struct grpc_resolver_vtable grpc_resolver_vtable;
+
+/** grpc_resolver provides grpc_client_config objects to grpc_channel
+    objects */
+struct grpc_resolver {
+  const grpc_resolver_vtable *vtable;
+  gpr_refcount refs;
+};
+
+struct grpc_resolver_vtable {
+  void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
+  void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
+  void (*channel_saw_error)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
+  void (*next)(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
+               grpc_client_config **target_config, grpc_closure *on_complete);
+};
+
+#ifdef GRPC_RESOLVER_REFCOUNT_DEBUG
+#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))
+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,
+                         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))
+void grpc_resolver_ref(grpc_resolver *policy);
+void grpc_resolver_unref(grpc_exec_ctx *exec_ctx, grpc_resolver *policy);
+#endif
+
+void grpc_resolver_init(grpc_resolver *resolver,
+                        const grpc_resolver_vtable *vtable);
+
+void grpc_resolver_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver);
+
+/** Notification that the channel has seen an error on some address.
+    Can be used as a hint that re-resolution is desirable soon. */
+void grpc_resolver_channel_saw_error(grpc_exec_ctx *exec_ctx,
+                                     grpc_resolver *resolver);
+
+/** Get the next client config. Called by the channel to fetch a new
+    configuration. Expected to set *target_config with a new configuration,
+    and then schedule on_complete for execution.
+
+    If resolution is fatally broken, set *target_config to NULL and
+    schedule on_complete. */
+void grpc_resolver_next(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver,
+                        grpc_client_config **target_config,
+                        grpc_closure *on_complete);
+
+#endif /* GRPC_CORE_LIB_CLIENT_CONFIG_RESOLVER_H */