Progress towards mdstr elimination

46 files changed, 509 insertions, 446 deletions

diff --git a/test/core/end2end/cq_verifier.c b/test/core/end2end/cq_verifier.c
index 6a463e8613..925c59e696 100644
--- a/test/core/end2end/cq_verifier.c
+++ b/test/core/end2end/cq_verifier.c
@@ -105,6 +105,23 @@ int contains_metadata(grpc_metadata_array *array, const char *key,
   return has_metadata(array->metadata, array->count, key, value);
 }
 
+static int has_metadata_slices(const grpc_metadata *md, size_t count,
+                               grpc_slice key, grpc_slice value) {
+  size_t i;
+  for (i = 0; i < count; i++) {
+    if (0 == grpc_slice_cmp(md[i].key, key) &&
+        0 == grpc_slice_cmp(md[i].value, value)) {
+      return 1;
+    }
+  }
+  return 0;
+}
+
+int contains_metadata_slices(grpc_metadata_array *array, grpc_slice key,
+                             grpc_slice value) {
+  return has_metadata_slices(array->metadata, array->count, key, value);
+}
+
 static grpc_slice merge_slices(grpc_slice *slices, size_t nslices) {
   size_t i;
   size_t len = 0;
diff --git a/test/core/end2end/cq_verifier.h b/test/core/end2end/cq_verifier.h
index b754de9bbe..035aa270e4 100644
--- a/test/core/end2end/cq_verifier.h
+++ b/test/core/end2end/cq_verifier.h
@@ -71,5 +71,7 @@ int byte_buffer_eq_slice(grpc_byte_buffer *bb, grpc_slice b);
 int byte_buffer_eq_string(grpc_byte_buffer *byte_buffer, const char *string);
 int contains_metadata(grpc_metadata_array *array, const char *key,
                       const char *value);
+int contains_metadata_slices(grpc_metadata_array *array, grpc_slice key,
+                             grpc_slice value);
 
 #endif /* GRPC_TEST_CORE_END2END_CQ_VERIFIER_H */
diff --git a/test/core/end2end/end2end_test_utils.c b/test/core/end2end/end2end_test_utils.c
index 46fb4ec1af..8783d8451b 100644
--- a/test/core/end2end/end2end_test_utils.c
+++ b/test/core/end2end/end2end_test_utils.c
@@ -39,13 +39,27 @@
 
 const char *get_host_override_string(const char *str,
                                      grpc_end2end_test_config config) {
-  return (config.feature_mask & FEATURE_MASK_SUPPORTS_AUTHORITY_HEADER ? str
-                                                                       : NULL);
+  if (config.feature_mask & FEATURE_MASK_SUPPORTS_AUTHORITY_HEADER) {
+    return str;
+  } else {
+    return NULL;
+  }
+}
+
+const grpc_slice *get_host_override_slice(const char *str,
+                                          grpc_end2end_test_config config) {
+  const char *r = get_host_override_string(str, config);
+  if (r != NULL) {
+    static grpc_slice ret;
+    ret = grpc_slice_from_static_string(r);
+    return &ret;
+  }
+  return NULL;
 }
 
-void validate_host_override_string(const char *pattern, const char *str,
+void validate_host_override_string(const char *pattern, grpc_slice str,
                                    grpc_end2end_test_config config) {
   if (config.feature_mask & FEATURE_MASK_SUPPORTS_AUTHORITY_HEADER) {
-    GPR_ASSERT(0 == strcmp(str, pattern));
+    GPR_ASSERT(0 == grpc_slice_str_cmp(str, pattern));
   }
 }
diff --git a/test/core/end2end/end2end_tests.h b/test/core/end2end/end2end_tests.h
index f25e90b5f6..cb0afd9cd9 100644
--- a/test/core/end2end/end2end_tests.h
+++ b/test/core/end2end/end2end_tests.h
@@ -72,8 +72,12 @@ void grpc_end2end_tests(int argc, char **argv, grpc_end2end_test_config config);
 
 const char *get_host_override_string(const char *str,
                                      grpc_end2end_test_config config);
+/* Returns a pointer to a statically allocated slice: future invocations
+   overwrite past invocations, not threadsafe, etc... */
+const grpc_slice *get_host_override_slice(const char *str,
+                                          grpc_end2end_test_config config);
 
-void validate_host_override_string(const char *pattern, const char *str,
+void validate_host_override_string(const char *pattern, grpc_slice str,
                                    grpc_end2end_test_config config);
 
 #endif /* GRPC_TEST_CORE_END2END_END2END_TESTS_H */
diff --git a/test/core/end2end/tests/authority_not_supported.c b/test/core/end2end/tests/authority_not_supported.c
index 705970f6ca..40d217e619 100644
--- a/test/core/end2end/tests/authority_not_supported.c
+++ b/test/core/end2end/tests/authority_not_supported.c
@@ -103,9 +103,14 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
   grpc_byte_buffer *request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   gpr_timespec deadline = five_seconds_time();
-  grpc_metadata meta_c[2] = {
-      {"key1", "val1", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key2", "val2", 4, 0, {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
+                              grpc_slice_from_static_string("val1"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key2"),
+                              grpc_slice_from_static_string("val2"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
   grpc_end2end_test_fixture f =
       begin_test(config, "test_with_authority_header", NULL, NULL);
   cq_verifier *cqv = cq_verifier_create(f.cq);
@@ -116,11 +121,12 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
+  grpc_slice host = grpc_slice_from_static_string("foo.test.google.fr");
   c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
-                               "/foo", "foo.test.google.fr", deadline, NULL);
+                               grpc_slice_from_static_string("/foo"), &host,
+                               deadline, NULL);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -157,7 +163,6 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -169,7 +174,7 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
 
   GPR_ASSERT(status == GRPC_STATUS_CANCELLED);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
 
diff --git a/test/core/end2end/tests/bad_hostname.c b/test/core/end2end/tests/bad_hostname.c
index e0c7ac7c02..f18abc78f0 100644
--- a/test/core/end2end/tests/bad_hostname.c
+++ b/test/core/end2end/tests/bad_hostname.c
@@ -109,11 +109,12 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
+  grpc_slice host = grpc_slice_from_static_string("slartibartfast.local");
   c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
-                               "/foo", "slartibartfast.local", deadline, NULL);
+                               grpc_slice_from_static_string("/foo"), &host,
+                               deadline, NULL);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -141,7 +142,6 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -153,7 +153,7 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
 
   GPR_ASSERT(status == GRPC_STATUS_INTERNAL);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/binary_metadata.c b/test/core/end2end/tests/binary_metadata.c
index a13613a472..bfdc7be544 100644
--- a/test/core/end2end/tests/binary_metadata.c
+++ b/test/core/end2end/tests/binary_metadata.c
@@ -110,25 +110,25 @@ static void test_request_response_with_metadata_and_payload(
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   gpr_timespec deadline = five_seconds_time();
   grpc_metadata meta_c[2] = {
-      {"key1-bin",
-       "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc",
-       13,
+      {grpc_slice_from_static_string("key1-bin"),
+       grpc_slice_from_static_string(
+           "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc"),
        0,
        {{NULL, NULL, NULL, NULL}}},
-      {"key2-bin",
-       "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d",
-       14,
+      {grpc_slice_from_static_string("key2-bin"),
+       grpc_slice_from_static_string(
+           "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d"),
        0,
        {{NULL, NULL, NULL, NULL}}}};
   grpc_metadata meta_s[2] = {
-      {"key3-bin",
-       "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee",
-       15,
+      {grpc_slice_from_static_string("key3-bin"),
+       grpc_slice_from_static_string(
+           "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee"),
        0,
        {{NULL, NULL, NULL, NULL}}},
-      {"key4-bin",
-       "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
-       16,
+      {grpc_slice_from_static_string("key4-bin"),
+       grpc_slice_from_static_string(
+           "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"),
        0,
        {{NULL, NULL, NULL, NULL}}}};
   grpc_end2end_test_fixture f = begin_test(
@@ -144,13 +144,13 @@ static void test_request_response_with_metadata_and_payload(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -190,7 +190,6 @@ static void test_request_response_with_metadata_and_payload(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -238,7 +237,8 @@ static void test_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_string = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_string;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -250,8 +250,8 @@ static void test_request_response_with_metadata_and_payload(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
@@ -270,7 +270,7 @@ static void test_request_response_with_metadata_and_payload(
       &initial_metadata_recv, "key4-bin",
       "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/call_creds.c b/test/core/end2end/tests/call_creds.c
index 606938fff6..ebc854606b 100644
--- a/test/core/end2end/tests/call_creds.c
+++ b/test/core/end2end/tests/call_creds.c
@@ -156,8 +156,7 @@ static void request_response_with_payload_and_call_creds(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   grpc_call_credentials *creds = NULL;
   grpc_auth_context *s_auth_context = NULL;
@@ -167,8 +166,9 @@ static void request_response_with_payload_and_call_creds(
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
   creds = grpc_google_iam_credentials_create(iam_token, iam_selector, NULL);
@@ -225,7 +225,6 @@ static void request_response_with_payload_and_call_creds(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -284,7 +283,8 @@ static void request_response_with_payload_and_call_creds(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -296,8 +296,8 @@ static void request_response_with_payload_and_call_creds(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
@@ -337,7 +337,7 @@ static void request_response_with_payload_and_call_creds(
       break;
   }
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -391,8 +391,7 @@ static void test_request_with_server_rejecting_client_creds(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
@@ -404,8 +403,9 @@ static void test_request_with_server_rejecting_client_creds(
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -425,7 +425,6 @@ static void test_request_with_server_rejecting_client_creds(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -468,7 +467,7 @@ static void test_request_with_server_rejecting_client_creds(
 
   grpc_byte_buffer_destroy(request_payload);
   grpc_byte_buffer_destroy(response_payload_recv);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   grpc_call_destroy(c);
 
diff --git a/test/core/end2end/tests/cancel_after_accept.c b/test/core/end2end/tests/cancel_after_accept.c
index c0beb456ad..a2301d725c 100644
--- a/test/core/end2end/tests/cancel_after_accept.c
+++ b/test/core/end2end/tests/cancel_after_accept.c
@@ -43,6 +43,7 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/metadata.h"
 #include "src/core/lib/transport/method_config.h"
 
@@ -118,8 +119,7 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_byte_buffer *request_payload_recv = NULL;
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_slice request_payload_slice =
@@ -136,13 +136,13 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   if (use_service_config) {
     gpr_timespec timeout = {5, 0, GPR_TIMESPAN};
     grpc_method_config_table_entry entry = {
-        grpc_mdstr_from_string("/service/method"),
+        grpc_slice_from_static_string("/service/method"),
         grpc_method_config_create(NULL, &timeout, NULL, NULL),
     };
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_method_config_table *method_config_table =
         grpc_method_config_table_create(1, &entry);
-    GRPC_MDSTR_UNREF(&exec_ctx, entry.method_name);
+    grpc_slice_unref_internal(&exec_ctx, entry.method_name);
     grpc_method_config_unref(&exec_ctx, entry.method_config);
     grpc_arg arg =
         grpc_method_config_table_create_channel_arg(method_config_table);
@@ -156,8 +156,9 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   cq_verifier *cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/service/method",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/service/method"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -172,7 +173,6 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -248,7 +248,7 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   grpc_byte_buffer_destroy(response_payload);
   grpc_byte_buffer_destroy(request_payload_recv);
   grpc_byte_buffer_destroy(response_payload_recv);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   grpc_call_destroy(c);
   grpc_call_destroy(s);
diff --git a/test/core/end2end/tests/cancel_after_client_done.c b/test/core/end2end/tests/cancel_after_client_done.c
index 7742f9d179..63b8150cb6 100644
--- a/test/core/end2end/tests/cancel_after_client_done.c
+++ b/test/core/end2end/tests/cancel_after_client_done.c
@@ -113,8 +113,7 @@ static void test_cancel_after_accept_and_writes_closed(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_byte_buffer *request_payload_recv = NULL;
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_slice request_payload_slice =
@@ -128,8 +127,9 @@ static void test_cancel_after_accept_and_writes_closed(
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -144,7 +144,6 @@ static void test_cancel_after_accept_and_writes_closed(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -224,7 +223,7 @@ static void test_cancel_after_accept_and_writes_closed(
   grpc_byte_buffer_destroy(response_payload);
   grpc_byte_buffer_destroy(request_payload_recv);
   grpc_byte_buffer_destroy(response_payload_recv);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   grpc_call_destroy(c);
   grpc_call_destroy(s);
diff --git a/test/core/end2end/tests/cancel_after_invoke.c b/test/core/end2end/tests/cancel_after_invoke.c
index c3c5418f20..216c363760 100644
--- a/test/core/end2end/tests/cancel_after_invoke.c
+++ b/test/core/end2end/tests/cancel_after_invoke.c
@@ -113,8 +113,7 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
@@ -122,8 +121,9 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -138,7 +138,6 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -183,7 +182,7 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
 
   grpc_byte_buffer_destroy(request_payload);
   grpc_byte_buffer_destroy(response_payload_recv);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   grpc_call_destroy(c);
 
diff --git a/test/core/end2end/tests/cancel_before_invoke.c b/test/core/end2end/tests/cancel_before_invoke.c
index d4842829c0..c198fd1713 100644
--- a/test/core/end2end/tests/cancel_before_invoke.c
+++ b/test/core/end2end/tests/cancel_before_invoke.c
@@ -111,8 +111,7 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_byte_buffer *response_payload_recv = NULL;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
@@ -120,8 +119,9 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -138,7 +138,6 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -181,7 +180,7 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
 
   grpc_byte_buffer_destroy(request_payload);
   grpc_byte_buffer_destroy(response_payload_recv);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   grpc_call_destroy(c);
 
diff --git a/test/core/end2end/tests/cancel_in_a_vacuum.c b/test/core/end2end/tests/cancel_in_a_vacuum.c
index 5be850b6ea..af919805c7 100644
--- a/test/core/end2end/tests/cancel_in_a_vacuum.c
+++ b/test/core/end2end/tests/cancel_in_a_vacuum.c
@@ -106,8 +106,9 @@ static void test_cancel_in_a_vacuum(grpc_end2end_test_config config,
   cq_verifier *v_client = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
diff --git a/test/core/end2end/tests/cancel_with_status.c b/test/core/end2end/tests/cancel_with_status.c
index 3aecaf7159..38f8c612d1 100644
--- a/test/core/end2end/tests/cancel_with_status.c
+++ b/test/core/end2end/tests/cancel_with_status.c
@@ -108,14 +108,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_metadata_array trailing_metadata_recv;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
   gpr_log(GPR_DEBUG, "test with %" PRIuPTR " ops", num_ops);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -128,7 +128,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -156,9 +155,9 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
 
diff --git a/test/core/end2end/tests/compressed_payload.c b/test/core/end2end/tests/compressed_payload.c
index d7efe7747b..847bc1a8c9 100644
--- a/test/core/end2end/tests/compressed_payload.c
+++ b/test/core/end2end/tests/compressed_payload.c
@@ -48,6 +48,7 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/call_test_only.h"
+#include "src/core/lib/transport/static_metadata.h"
 #include "test/core/end2end/cq_verifier.h"
 
 static void *tag(intptr_t t) { return (void *)t; }
@@ -125,8 +126,7 @@ static void request_for_disabled_algorithm(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   cq_verifier *cqv;
   char str[1024];
@@ -151,8 +151,9 @@ static void request_for_disabled_algorithm(
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -191,7 +192,6 @@ static void request_for_disabled_algorithm(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -245,13 +245,13 @@ static void request_for_disabled_algorithm(
   gpr_asprintf(&expected_details, "Compression algorithm '%s' is disabled.",
                algo_name);
   /* and we expect a specific reason for it */
-  GPR_ASSERT(0 == strcmp(details, expected_details));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, expected_details));
   gpr_free(expected_details);
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -305,8 +305,7 @@ static void request_with_payload_template(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   cq_verifier *cqv;
   char request_str[1024];
@@ -331,8 +330,9 @@ static void request_with_payload_template(
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -362,7 +362,6 @@ static void request_with_payload_template(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -489,7 +488,8 @@ static void request_with_payload_template(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -503,13 +503,13 @@ static void request_with_payload_template(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -569,17 +569,14 @@ static void test_invoke_request_with_compressed_payload_md_override(
   grpc_metadata gzip_compression_override;
   grpc_metadata identity_compression_override;
 
-  gzip_compression_override.key = GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY;
-  gzip_compression_override.value = "gzip";
-  gzip_compression_override.value_length =
-      strlen(gzip_compression_override.value);
+  gzip_compression_override.key = GRPC_MDSTR_GRPC_INTERNAL_ENCODING_REQUEST;
+  gzip_compression_override.value = grpc_slice_from_static_string("gzip");
   memset(&gzip_compression_override.internal_data, 0,
          sizeof(gzip_compression_override.internal_data));
 
-  identity_compression_override.key = GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY;
-  identity_compression_override.value = "identity";
-  identity_compression_override.value_length =
-      strlen(identity_compression_override.value);
+  identity_compression_override.key = GRPC_MDSTR_GRPC_INTERNAL_ENCODING_REQUEST;
+  identity_compression_override.value =
+      grpc_slice_from_static_string("identity");
   memset(&identity_compression_override.internal_data, 0,
          sizeof(identity_compression_override.internal_data));
 
diff --git a/test/core/end2end/tests/default_host.c b/test/core/end2end/tests/default_host.c
index 208e31697e..0c39957fa7 100644
--- a/test/core/end2end/tests/default_host.c
+++ b/test/core/end2end/tests/default_host.c
@@ -110,13 +110,13 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   char *peer;
 
   c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
-                               "/foo", NULL, deadline, NULL);
+                               grpc_slice_from_static_string("/foo"), NULL,
+                               deadline, NULL);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
@@ -149,7 +149,6 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -182,7 +181,8 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -199,12 +199,12 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
-  GPR_ASSERT(0 == strncmp(call_details.host, "localhost", 9));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
+  GPR_ASSERT(grpc_slice_buf_start_eq(call_details.host, "localhost", 9));
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/disappearing_server.c b/test/core/end2end/tests/disappearing_server.c
index 8ebf7e643e..a01372144c 100644
--- a/test/core/end2end/tests/disappearing_server.c
+++ b/test/core/end2end/tests/disappearing_server.c
@@ -93,13 +93,13 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -128,7 +128,6 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -156,7 +155,8 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -174,13 +174,13 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/empty_batch.c b/test/core/end2end/tests/empty_batch.c
index dc8e52a60f..1b420ad4cb 100644
--- a/test/core/end2end/tests/empty_batch.c
+++ b/test/core/end2end/tests/empty_batch.c
@@ -106,8 +106,9 @@ static void empty_batch_body(grpc_end2end_test_config config,
   grpc_op *op = NULL;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
diff --git a/test/core/end2end/tests/filter_call_init_fails.c b/test/core/end2end/tests/filter_call_init_fails.c
index 01b6c32ee7..5546893ea0 100644
--- a/test/core/end2end/tests/filter_call_init_fails.c
+++ b/test/core/end2end/tests/filter_call_init_fails.c
@@ -125,12 +125,12 @@ static void test_request(grpc_end2end_test_config config) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -165,7 +165,6 @@ static void test_request(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -181,9 +180,9 @@ static void test_request(grpc_end2end_test_config config) {
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_PERMISSION_DENIED);
-  GPR_ASSERT(0 == strcmp(details, "access denied"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "access denied"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/filter_causes_close.c b/test/core/end2end/tests/filter_causes_close.c
index def21be43f..45040ab351 100644
--- a/test/core/end2end/tests/filter_causes_close.c
+++ b/test/core/end2end/tests/filter_causes_close.c
@@ -121,12 +121,12 @@ static void test_request(grpc_end2end_test_config config) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -161,7 +161,6 @@ static void test_request(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -177,9 +176,10 @@ static void test_request(grpc_end2end_test_config config) {
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_PERMISSION_DENIED);
-  GPR_ASSERT(0 == strcmp(details, "Failure that's not preventable."));
+  GPR_ASSERT(0 ==
+             grpc_slice_str_cmp(details, "Failure that's not preventable."));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/graceful_server_shutdown.c b/test/core/end2end/tests/graceful_server_shutdown.c
index 5fecadbe44..08af25dd28 100644
--- a/test/core/end2end/tests/graceful_server_shutdown.c
+++ b/test/core/end2end/tests/graceful_server_shutdown.c
@@ -107,13 +107,13 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -143,7 +143,6 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -171,7 +170,8 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -191,12 +191,12 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_call_destroy(s);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/high_initial_seqno.c b/test/core/end2end/tests/high_initial_seqno.c
index 01a4909ccd..217ca2bb72 100644
--- a/test/core/end2end/tests/high_initial_seqno.c
+++ b/test/core/end2end/tests/high_initial_seqno.c
@@ -113,13 +113,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -148,7 +148,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -172,7 +171,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -189,13 +189,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/hpack_size.c b/test/core/end2end/tests/hpack_size.c
index cec8b2faae..9aedc9c143 100644
--- a/test/core/end2end/tests/hpack_size.c
+++ b/test/core/end2end/tests/hpack_size.c
@@ -254,24 +254,24 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_status_code status;
   grpc_call_error error;
   grpc_metadata extra_metadata[3];
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   memset(extra_metadata, 0, sizeof(extra_metadata));
-  extra_metadata[0].key = "hobbit-first-name";
-  extra_metadata[0].value = hobbits[index % GPR_ARRAY_SIZE(hobbits)][0];
-  extra_metadata[0].value_length = strlen(extra_metadata[0].value);
-  extra_metadata[1].key = "hobbit-second-name";
-  extra_metadata[1].value = hobbits[index % GPR_ARRAY_SIZE(hobbits)][1];
-  extra_metadata[1].value_length = strlen(extra_metadata[1].value);
-  extra_metadata[2].key = "dragon";
-  extra_metadata[2].value = dragons[index % GPR_ARRAY_SIZE(dragons)];
-  extra_metadata[2].value_length = strlen(extra_metadata[2].value);
+  extra_metadata[0].key = grpc_slice_from_static_string("hobbit-first-name");
+  extra_metadata[0].value = grpc_slice_from_static_string(
+      hobbits[index % GPR_ARRAY_SIZE(hobbits)][0]);
+  extra_metadata[1].key = grpc_slice_from_static_string("hobbit-second-name");
+  extra_metadata[1].value = grpc_slice_from_static_string(
+      hobbits[index % GPR_ARRAY_SIZE(hobbits)][1]);
+  extra_metadata[2].key = grpc_slice_from_static_string("dragon");
+  extra_metadata[2].value =
+      grpc_slice_from_static_string(dragons[index % GPR_ARRAY_SIZE(dragons)]);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -301,7 +301,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -325,7 +324,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -342,13 +342,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/idempotent_request.c b/test/core/end2end/tests/idempotent_request.c
index 4f6d3bb808..2db7accaaa 100644
--- a/test/core/end2end/tests/idempotent_request.c
+++ b/test/core/end2end/tests/idempotent_request.c
@@ -111,14 +111,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   char *peer;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -152,7 +152,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -185,7 +184,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -202,14 +202,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST == call_details.flags);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/invoke_large_request.c b/test/core/end2end/tests/invoke_large_request.c
index 24abfa2ea0..e18953a641 100644
--- a/test/core/end2end/tests/invoke_large_request.c
+++ b/test/core/end2end/tests/invoke_large_request.c
@@ -140,13 +140,13 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -185,7 +185,6 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -232,7 +231,8 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -244,13 +244,13 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/large_metadata.c b/test/core/end2end/tests/large_metadata.c
index 69b4b24b06..b45ceb2664 100644
--- a/test/core/end2end/tests/large_metadata.c
+++ b/test/core/end2end/tests/large_metadata.c
@@ -122,21 +122,19 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
-  meta.key = "key";
-  meta.value = gpr_malloc(large_size + 1);
-  memset((char *)meta.value, 'a', large_size);
-  ((char *)meta.value)[large_size] = 0;
-  meta.value_length = large_size;
+  meta.key = grpc_slice_from_static_string("key");
+  meta.value = grpc_slice_malloc(large_size);
+  memset(GRPC_SLICE_START_PTR(meta.value), 'a', large_size);
 
   grpc_metadata_array_init(&initial_metadata_recv);
   grpc_metadata_array_init(&trailing_metadata_recv);
@@ -170,7 +168,6 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -216,7 +213,8 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -228,15 +226,17 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
   GPR_ASSERT(byte_buffer_eq_string(request_payload_recv, "hello world"));
-  GPR_ASSERT(contains_metadata(&request_metadata_recv, "key", meta.value));
+  GPR_ASSERT(contains_metadata_slices(&request_metadata_recv,
+                                      grpc_slice_from_static_string("key"),
+                                      meta.value));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -250,7 +250,7 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   grpc_byte_buffer_destroy(request_payload);
   grpc_byte_buffer_destroy(request_payload_recv);
 
-  gpr_free((char *)meta.value);
+  grpc_slice_unref(meta.value);
 
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/load_reporting_hook.c b/test/core/end2end/tests/load_reporting_hook.c
index ae5c270629..edc4251119 100644
--- a/test/core/end2end/tests/load_reporting_hook.c
+++ b/test/core/end2end/tests/load_reporting_hook.c
@@ -146,13 +146,13 @@ static void request_response_with_payload(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, method_name,
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string(method_name),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -193,7 +193,6 @@ static void request_response_with_payload(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -242,7 +241,8 @@ static void request_response_with_payload(
   op->data.send_status_from_server.trailing_metadata_count = 1;
   op->data.send_status_from_server.trailing_metadata = trailing_lr_metadata;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -255,7 +255,7 @@ static void request_response_with_payload(
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -295,15 +295,13 @@ static void test_load_reporting_hook(grpc_end2end_test_config config) {
   grpc_metadata initial_lr_metadata;
   grpc_metadata trailing_lr_metadata;
 
-  initial_lr_metadata.key = GRPC_LB_TOKEN_MD_KEY;
-  initial_lr_metadata.value = "client-token";
-  initial_lr_metadata.value_length = strlen(initial_lr_metadata.value);
+  initial_lr_metadata.key = GRPC_MDSTR_LB_TOKEN;
+  initial_lr_metadata.value = grpc_slice_from_static_string("client-token");
   memset(&initial_lr_metadata.internal_data, 0,
          sizeof(initial_lr_metadata.internal_data));
 
-  trailing_lr_metadata.key = GRPC_LB_COST_MD_KEY;
-  trailing_lr_metadata.value = "server-token";
-  trailing_lr_metadata.value_length = strlen(trailing_lr_metadata.value);
+  trailing_lr_metadata.key = GRPC_MDSTR_LB_COST_BIN;
+  trailing_lr_metadata.value = grpc_slice_from_static_string("server-token");
   memset(&trailing_lr_metadata.internal_data, 0,
          sizeof(trailing_lr_metadata.internal_data));
 
diff --git a/test/core/end2end/tests/max_concurrent_streams.c b/test/core/end2end/tests/max_concurrent_streams.c
index 9338bc5f0d..56243179b0 100644
--- a/test/core/end2end/tests/max_concurrent_streams.c
+++ b/test/core/end2end/tests/max_concurrent_streams.c
@@ -109,13 +109,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -144,7 +144,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -168,7 +167,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -185,13 +185,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -223,11 +223,9 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   grpc_metadata_array trailing_metadata_recv2;
   grpc_status_code status1;
   grpc_call_error error;
-  char *details1 = NULL;
-  size_t details_capacity1 = 0;
+  grpc_slice details1;
   grpc_status_code status2;
-  char *details2 = NULL;
-  size_t details_capacity2 = 0;
+  grpc_slice details2;
   grpc_op ops[6];
   grpc_op *op;
   int was_cancelled;
@@ -261,13 +259,15 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
      the first completes */
   deadline = n_seconds_time(1000);
   c1 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/alpha",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/alpha"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c1);
   c2 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/beta",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/beta"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c2);
 
@@ -295,7 +295,6 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv1;
   op->data.recv_status_on_client.status = &status1;
   op->data.recv_status_on_client.status_details = &details1;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity1;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -327,7 +326,6 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv2;
   op->data.recv_status_on_client.status = &status2;
   op->data.recv_status_on_client.status_details = &details2;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity2;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -378,7 +376,8 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -413,7 +412,7 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -431,8 +430,8 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   grpc_call_destroy(c2);
   grpc_call_destroy(s2);
 
-  gpr_free(details1);
-  gpr_free(details2);
+  grpc_slice_unref(details1);
+  grpc_slice_unref(details2);
   grpc_metadata_array_destroy(&initial_metadata_recv1);
   grpc_metadata_array_destroy(&trailing_metadata_recv1);
   grpc_metadata_array_destroy(&initial_metadata_recv2);
diff --git a/test/core/end2end/tests/max_message_length.c b/test/core/end2end/tests/max_message_length.c
index ec85f3cb5d..3fbb92863c 100644
--- a/test/core/end2end/tests/max_message_length.c
+++ b/test/core/end2end/tests/max_message_length.c
@@ -43,6 +43,7 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/metadata.h"
 #include "src/core/lib/transport/method_config.h"
 
@@ -129,8 +130,7 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   grpc_channel_args *client_args = NULL;
@@ -141,12 +141,12 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
     GPR_ASSERT(send_limit);
     int32_t max_request_message_bytes = 5;
     grpc_method_config_table_entry entry = {
-        grpc_mdstr_from_string("/service/method"),
+        grpc_slice_from_static_string("/service/method"),
         grpc_method_config_create(NULL, NULL, &max_request_message_bytes, NULL),
     };
     grpc_method_config_table *method_config_table =
         grpc_method_config_table_create(1, &entry);
-    GRPC_MDSTR_UNREF(&exec_ctx, entry.method_name);
+    grpc_slice_unref_internal(&exec_ctx, entry.method_name);
     grpc_method_config_unref(&exec_ctx, entry.method_config);
     grpc_arg arg =
         grpc_method_config_table_create_channel_arg(method_config_table);
@@ -180,8 +180,9 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/service/method",
-      get_host_override_string("foo.test.google.fr:1234", config),
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/service/method"),
+      get_host_override_slice("foo.test.google.fr:1234", config),
       gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
   GPR_ASSERT(c);
 
@@ -215,7 +216,6 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -254,19 +254,20 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
 
-  GPR_ASSERT(0 == strcmp(call_details.method, "/service/method"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/service/method"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
 done:
   GPR_ASSERT(status == GRPC_STATUS_INVALID_ARGUMENT);
-  GPR_ASSERT(strcmp(details,
-                    send_limit
-                        ? "Sent message larger than max (11 vs. 5)"
-                        : "Received message larger than max (11 vs. 5)") == 0);
+  GPR_ASSERT(
+      grpc_slice_str_cmp(
+          details, send_limit
+                       ? "Sent message larger than max (11 vs. 5)"
+                       : "Received message larger than max (11 vs. 5)") == 0);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
@@ -309,8 +310,7 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   grpc_channel_args *client_args = NULL;
@@ -321,13 +321,13 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
     GPR_ASSERT(!send_limit);
     int32_t max_response_message_bytes = 5;
     grpc_method_config_table_entry entry = {
-        grpc_mdstr_from_string("/service/method"),
+        grpc_slice_from_static_string("/service/method"),
         grpc_method_config_create(NULL, NULL, NULL,
                                   &max_response_message_bytes),
     };
     grpc_method_config_table *method_config_table =
         grpc_method_config_table_create(1, &entry);
-    GRPC_MDSTR_UNREF(&exec_ctx, entry.method_name);
+    grpc_slice_unref_internal(&exec_ctx, entry.method_name);
     grpc_method_config_unref(&exec_ctx, entry.method_config);
     grpc_arg arg =
         grpc_method_config_table_create_channel_arg(method_config_table);
@@ -359,9 +359,11 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   }
   cqv = cq_verifier_create(f.cq);
 
-  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
-                               "/service/method", "foo.test.google.fr:1234",
-                               gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  c = grpc_channel_create_call(
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/service/method"),
+      get_host_override_slice("foo.test.google.fr:1234", config),
+      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -394,7 +396,6 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -428,7 +429,8 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -439,16 +441,18 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
 
-  GPR_ASSERT(0 == strcmp(call_details.method, "/service/method"));
-  GPR_ASSERT(0 == strcmp(call_details.host, "foo.test.google.fr:1234"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/service/method"));
+  GPR_ASSERT(0 ==
+             grpc_slice_str_cmp(call_details.host, "foo.test.google.fr:1234"));
 
   GPR_ASSERT(status == GRPC_STATUS_INVALID_ARGUMENT);
-  GPR_ASSERT(strcmp(details,
-                    send_limit
-                        ? "Sent message larger than max (11 vs. 5)"
-                        : "Received message larger than max (11 vs. 5)") == 0);
+  GPR_ASSERT(
+      grpc_slice_str_cmp(
+          details, send_limit
+                       ? "Sent message larger than max (11 vs. 5)"
+                       : "Received message larger than max (11 vs. 5)") == 0);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/negative_deadline.c b/test/core/end2end/tests/negative_deadline.c
index 929777d39e..403386b5e7 100644
--- a/test/core/end2end/tests/negative_deadline.c
+++ b/test/core/end2end/tests/negative_deadline.c
@@ -108,14 +108,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_metadata_array trailing_metadata_recv;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
 
   gpr_log(GPR_DEBUG, "test with %" PRIuPTR " ops", num_ops);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -128,7 +128,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -155,7 +154,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   GPR_ASSERT(status == GRPC_STATUS_DEADLINE_EXCEEDED);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
 
diff --git a/test/core/end2end/tests/network_status_change.c b/test/core/end2end/tests/network_status_change.c
index 2ebda2ccb8..6cfeaa851a 100644
--- a/test/core/end2end/tests/network_status_change.c
+++ b/test/core/end2end/tests/network_status_change.c
@@ -119,13 +119,13 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -159,7 +159,6 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -201,7 +200,8 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -214,11 +214,11 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
 
   // Expected behavior of a RPC when network is lost.
   GPR_ASSERT(status == GRPC_STATUS_UNAVAILABLE);
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/no_logging.c b/test/core/end2end/tests/no_logging.c
index 54614cb029..5c22631bad 100644
--- a/test/core/end2end/tests/no_logging.c
+++ b/test/core/end2end/tests/no_logging.c
@@ -139,14 +139,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   char *peer;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -179,7 +179,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -210,7 +209,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -227,14 +227,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(0 == call_details.flags);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/payload.c b/test/core/end2end/tests/payload.c
index db2e5c83de..dd989e3ad6 100644
--- a/test/core/end2end/tests/payload.c
+++ b/test/core/end2end/tests/payload.c
@@ -138,13 +138,13 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -183,7 +183,6 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -230,7 +229,8 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -242,8 +242,8 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
@@ -251,7 +251,7 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   GPR_ASSERT(
       byte_buffer_eq_slice(response_payload_recv, response_payload_slice));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/ping_pong_streaming.c b/test/core/end2end/tests/ping_pong_streaming.c
index 0a1566e9c2..b69b7f27a6 100644
--- a/test/core/end2end/tests/ping_pong_streaming.c
+++ b/test/core/end2end/tests/ping_pong_streaming.c
@@ -112,8 +112,7 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   grpc_byte_buffer *request_payload;
   grpc_byte_buffer *request_payload_recv;
@@ -126,8 +125,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
       grpc_slice_from_copied_string("hello you");
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -152,7 +152,6 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -248,7 +247,8 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -270,7 +270,7 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
   grpc_call_details_destroy(&call_details);
-  gpr_free(details);
+  grpc_slice_unref(details);
 
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/registered_call.c b/test/core/end2end/tests/registered_call.c
index 6594b420b9..e0716737a3 100644
--- a/test/core/end2end/tests/registered_call.c
+++ b/test/core/end2end/tests/registered_call.c
@@ -111,8 +111,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_registered_call(
@@ -144,7 +143,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -168,7 +166,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -185,13 +184,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/request_with_flags.c b/test/core/end2end/tests/request_with_flags.c
index 9c18e155f3..cd92b484a3 100644
--- a/test/core/end2end/tests/request_with_flags.c
+++ b/test/core/end2end/tests/request_with_flags.c
@@ -117,13 +117,13 @@ static void test_invoke_request_with_flags(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   grpc_call_error expectation;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -157,7 +157,6 @@ static void test_invoke_request_with_flags(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = flags_for_op[op->op];
   op->reserved = NULL;
   op++;
@@ -170,7 +169,7 @@ static void test_invoke_request_with_flags(
     cq_verify(cqv);
   }
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/request_with_payload.c b/test/core/end2end/tests/request_with_payload.c
index c84e3ac5b5..3258c0451b 100644
--- a/test/core/end2end/tests/request_with_payload.c
+++ b/test/core/end2end/tests/request_with_payload.c
@@ -116,13 +116,13 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -156,7 +156,6 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -197,7 +196,8 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -209,14 +209,14 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
   GPR_ASSERT(byte_buffer_eq_string(request_payload_recv, "hello world"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/resource_quota_server.c b/test/core/end2end/tests/resource_quota_server.c
index 7ec33e97a3..15d7734311 100644
--- a/test/core/end2end/tests/resource_quota_server.c
+++ b/test/core/end2end/tests/resource_quota_server.c
@@ -149,8 +149,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
   grpc_call_details *call_details =
       malloc(sizeof(grpc_call_details) * NUM_CALLS);
   grpc_status_code *status = malloc(sizeof(grpc_status_code) * NUM_CALLS);
-  char **details = malloc(sizeof(char *) * NUM_CALLS);
-  size_t *details_capacity = malloc(sizeof(size_t) * NUM_CALLS);
+  grpc_slice *details = malloc(sizeof(char *) * NUM_CALLS);
   grpc_byte_buffer **request_payload_recv =
       malloc(sizeof(grpc_byte_buffer *) * NUM_CALLS);
   int *was_cancelled = malloc(sizeof(int) * NUM_CALLS);
@@ -173,8 +172,6 @@ void resource_quota_server(grpc_end2end_test_config config) {
     grpc_metadata_array_init(&trailing_metadata_recv[i]);
     grpc_metadata_array_init(&request_metadata_recv[i]);
     grpc_call_details_init(&call_details[i]);
-    details[i] = NULL;
-    details_capacity[i] = 0;
     request_payload_recv[i] = NULL;
     was_cancelled[i] = 0;
   }
@@ -190,8 +187,10 @@ void resource_quota_server(grpc_end2end_test_config config) {
 
   for (int i = 0; i < NUM_CALLS; i++) {
     client_calls[i] = grpc_channel_create_call(
-        f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-        "foo.test.google.fr", n_seconds_time(60), NULL);
+        f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+        grpc_slice_from_static_string("/foo"),
+        get_host_override_slice("foo.test.google.fr", config),
+        n_seconds_time(60), NULL);
 
     memset(ops, 0, sizeof(ops));
     op = ops;
@@ -219,8 +218,6 @@ void resource_quota_server(grpc_end2end_test_config config) {
         &trailing_metadata_recv[i];
     op->data.recv_status_on_client.status = &status[i];
     op->data.recv_status_on_client.status_details = &details[i];
-    op->data.recv_status_on_client.status_details_capacity =
-        &details_capacity[i];
     op->flags = 0;
     op->reserved = NULL;
     op++;
@@ -260,7 +257,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
       grpc_metadata_array_destroy(&initial_metadata_recv[call_id]);
       grpc_metadata_array_destroy(&trailing_metadata_recv[call_id]);
       grpc_call_destroy(client_calls[call_id]);
-      gpr_free(details[call_id]);
+      grpc_slice_unref(details[call_id]);
 
       pending_client_calls--;
     } else if (ev_tag < SERVER_RECV_BASE_TAG) {
@@ -317,7 +314,8 @@ void resource_quota_server(grpc_end2end_test_config config) {
       op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
       op->data.send_status_from_server.trailing_metadata_count = 0;
       op->data.send_status_from_server.status = GRPC_STATUS_OK;
-      op->data.send_status_from_server.status_details = "xyz";
+      grpc_slice status_details = grpc_slice_from_static_string("xyz");
+      op->data.send_status_from_server.status_details = &status_details;
       op->flags = 0;
       op->reserved = NULL;
       op++;
@@ -370,7 +368,6 @@ void resource_quota_server(grpc_end2end_test_config config) {
   free(call_details);
   free(status);
   free(details);
-  free(details_capacity);
   free(request_payload_recv);
   free(was_cancelled);
 
diff --git a/test/core/end2end/tests/server_finishes_request.c b/test/core/end2end/tests/server_finishes_request.c
index 3bb25fd924..ee18c6817b 100644
--- a/test/core/end2end/tests/server_finishes_request.c
+++ b/test/core/end2end/tests/server_finishes_request.c
@@ -111,13 +111,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -142,7 +142,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -166,7 +165,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -183,13 +183,13 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/shutdown_finishes_calls.c b/test/core/end2end/tests/shutdown_finishes_calls.c
index b80a2e35f2..0be5315360 100644
--- a/test/core/end2end/tests/shutdown_finishes_calls.c
+++ b/test/core/end2end/tests/shutdown_finishes_calls.c
@@ -100,13 +100,13 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -136,7 +136,6 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -172,12 +171,12 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_server_destroy(f.server);
 
   GPR_ASSERT(status == GRPC_STATUS_UNAVAILABLE);
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/simple_cacheable_request.c b/test/core/end2end/tests/simple_cacheable_request.c
index 2c229b08fe..ea916e7b3a 100644
--- a/test/core/end2end/tests/simple_cacheable_request.c
+++ b/test/core/end2end/tests/simple_cacheable_request.c
@@ -111,12 +111,22 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   grpc_byte_buffer *response_payload =
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   gpr_timespec deadline = five_seconds_time();
-  grpc_metadata meta_c[2] = {
-      {"key1", "val1", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key2", "val2", 4, 0, {{NULL, NULL, NULL, NULL}}}};
-  grpc_metadata meta_s[2] = {
-      {"key3", "val3", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key4", "val4", 4, 0, {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
+                              grpc_slice_from_static_string("val1"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key2"),
+                              grpc_slice_from_static_string("val2"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
+                              grpc_slice_from_static_string("val3"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key4"),
+                              grpc_slice_from_static_string("val4"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
   grpc_end2end_test_fixture f = begin_test(
       config, "test_cacheable_request_response_with_metadata_and_payload", NULL,
       NULL);
@@ -131,13 +141,13 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -177,7 +187,6 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -225,7 +234,8 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -237,8 +247,8 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   if (config.feature_mask & FEATURE_MASK_SUPPORTS_REQUEST_PROXYING) {
@@ -254,7 +264,7 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   GPR_ASSERT(contains_metadata(&initial_metadata_recv, "key3", "val3"));
   GPR_ASSERT(contains_metadata(&initial_metadata_recv, "key4", "val4"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/simple_delayed_request.c b/test/core/end2end/tests/simple_delayed_request.c
index ec40c8f22d..83ad8515df 100644
--- a/test/core/end2end/tests/simple_delayed_request.c
+++ b/test/core/end2end/tests/simple_delayed_request.c
@@ -100,15 +100,15 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   config.init_client(f, client_args);
 
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -137,7 +137,6 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -163,7 +162,8 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -180,13 +180,13 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/simple_metadata.c b/test/core/end2end/tests/simple_metadata.c
index 5490cc2b75..162c89c618 100644
--- a/test/core/end2end/tests/simple_metadata.c
+++ b/test/core/end2end/tests/simple_metadata.c
@@ -109,12 +109,22 @@ static void test_request_response_with_metadata_and_payload(
   grpc_byte_buffer *response_payload =
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   gpr_timespec deadline = five_seconds_time();
-  grpc_metadata meta_c[2] = {
-      {"key1", "val1", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key2", "val2", 4, 0, {{NULL, NULL, NULL, NULL}}}};
-  grpc_metadata meta_s[2] = {
-      {"key3", "val3", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key4", "val4", 4, 0, {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
+                              grpc_slice_from_static_string("val1"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key2"),
+                              grpc_slice_from_static_string("val2"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
+                              grpc_slice_from_static_string("val3"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key4"),
+                              grpc_slice_from_static_string("val4"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
   grpc_end2end_test_fixture f = begin_test(
       config, "test_request_response_with_metadata_and_payload", NULL, NULL);
   cq_verifier *cqv = cq_verifier_create(f.cq);
@@ -128,13 +138,13 @@ static void test_request_response_with_metadata_and_payload(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -174,7 +184,6 @@ static void test_request_response_with_metadata_and_payload(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -222,7 +231,8 @@ static void test_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -234,8 +244,8 @@ static void test_request_response_with_metadata_and_payload(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 0);
@@ -246,7 +256,7 @@ static void test_request_response_with_metadata_and_payload(
   GPR_ASSERT(contains_metadata(&initial_metadata_recv, "key3", "val3"));
   GPR_ASSERT(contains_metadata(&initial_metadata_recv, "key4", "val4"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/simple_request.c b/test/core/end2end/tests/simple_request.c
index 2dea5d6af2..e0a69826c4 100644
--- a/test/core/end2end/tests/simple_request.c
+++ b/test/core/end2end/tests/simple_request.c
@@ -111,14 +111,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
   char *peer;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -152,7 +152,6 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -185,7 +184,8 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -202,14 +202,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(0 == call_details.flags);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/streaming_error_response.c b/test/core/end2end/tests/streaming_error_response.c
index 583bc9268f..05012523a7 100644
--- a/test/core/end2end/tests/streaming_error_response.c
+++ b/test/core/end2end/tests/streaming_error_response.c
@@ -121,13 +121,13 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -154,7 +154,6 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
     op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
     op->data.recv_status_on_client.status = &status;
     op->data.recv_status_on_client.status_details = &details;
-    op->data.recv_status_on_client.status_details_capacity = &details_capacity;
     op++;
   }
   error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
@@ -202,7 +201,8 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_FAILED_PRECONDITION;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op++;
   error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
   GPR_ASSERT(GRPC_CALL_OK == error);
@@ -232,7 +232,6 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
     op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
     op->data.recv_status_on_client.status = &status;
     op->data.recv_status_on_client.status_details = &details;
-    op->data.recv_status_on_client.status_details_capacity = &details_capacity;
     op++;
     error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
     GPR_ASSERT(GRPC_CALL_OK == error);
@@ -245,13 +244,13 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   }
 
   GPR_ASSERT(status == GRPC_STATUS_FAILED_PRECONDITION);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(was_cancelled == 1);
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);
diff --git a/test/core/end2end/tests/trailing_metadata.c b/test/core/end2end/tests/trailing_metadata.c
index 9fd4fbc052..b6741dbf3d 100644
--- a/test/core/end2end/tests/trailing_metadata.c
+++ b/test/core/end2end/tests/trailing_metadata.c
@@ -109,15 +109,30 @@ static void test_request_response_with_metadata_and_payload(
   grpc_byte_buffer *response_payload =
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   gpr_timespec deadline = five_seconds_time();
-  grpc_metadata meta_c[2] = {
-      {"key1", "val1", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key2", "val2", 4, 0, {{NULL, NULL, NULL, NULL}}}};
-  grpc_metadata meta_s[2] = {
-      {"key3", "val3", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key4", "val4", 4, 0, {{NULL, NULL, NULL, NULL}}}};
-  grpc_metadata meta_t[2] = {
-      {"key5", "val5", 4, 0, {{NULL, NULL, NULL, NULL}}},
-      {"key6", "val6", 4, 0, {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
+                              grpc_slice_from_static_string("val1"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key2"),
+                              grpc_slice_from_static_string("val2"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
+                              grpc_slice_from_static_string("val3"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key4"),
+                              grpc_slice_from_static_string("val4"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
+  grpc_metadata meta_t[2] = {{grpc_slice_from_static_string("key5"),
+                              grpc_slice_from_static_string("val5"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}},
+                             {grpc_slice_from_static_string("key6"),
+                              grpc_slice_from_static_string("val6"),
+                              0,
+                              {{NULL, NULL, NULL, NULL}}}};
   grpc_end2end_test_fixture f = begin_test(
       config, "test_request_response_with_metadata_and_payload", NULL, NULL);
   cq_verifier *cqv = cq_verifier_create(f.cq);
@@ -131,13 +146,13 @@ static void test_request_response_with_metadata_and_payload(
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
-  char *details = NULL;
-  size_t details_capacity = 0;
+  grpc_slice details;
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      grpc_slice_from_static_string("/foo"),
+      get_host_override_slice("foo.test.google.fr:1234", config), deadline,
       NULL);
   GPR_ASSERT(c);
 
@@ -177,7 +192,6 @@ static void test_request_response_with_metadata_and_payload(
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
-  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -226,7 +240,8 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_status_from_server.trailing_metadata_count = 2;
   op->data.send_status_from_server.trailing_metadata = meta_t;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
-  op->data.send_status_from_server.status_details = "xyz";
+  grpc_slice status_details = grpc_slice_from_static_string("xyz");
+  op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -238,8 +253,8 @@ static void test_request_response_with_metadata_and_payload(
   cq_verify(cqv);
 
   GPR_ASSERT(status == GRPC_STATUS_OK);
-  GPR_ASSERT(0 == strcmp(details, "xyz"));
-  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(details, "xyz"));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
   validate_host_override_string("foo.test.google.fr:1234", call_details.host,
                                 config);
   GPR_ASSERT(byte_buffer_eq_string(request_payload_recv, "hello world"));
@@ -251,7 +266,7 @@ static void test_request_response_with_metadata_and_payload(
   GPR_ASSERT(contains_metadata(&trailing_metadata_recv, "key5", "val5"));
   GPR_ASSERT(contains_metadata(&trailing_metadata_recv, "key6", "val6"));
 
-  gpr_free(details);
+  grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_metadata_array_destroy(&request_metadata_recv);