Merge master after no Extern C changes

35 files changed, 18 insertions, 234 deletions

diff --git a/src/core/ext/filters/client_channel/client_channel.h b/src/core/ext/filters/client_channel/client_channel.h
index 170ad451bd..9670405cbe 100644
--- a/src/core/ext/filters/client_channel/client_channel.h
+++ b/src/core/ext/filters/client_channel/client_channel.h
@@ -28,10 +28,6 @@ extern grpc_core::TraceFlag grpc_client_channel_trace;
 // Channel arg key for server URI string.
 #define GRPC_ARG_SERVER_URI "grpc.server_uri"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* A client channel is a channel that begins disconnected, and can connect
    to some endpoint on demand. If that endpoint disconnects, it will be
    connected to again later.
@@ -56,8 +52,4 @@ void grpc_client_channel_watch_connectivity_state(
 grpc_subchannel_call* grpc_client_channel_get_subchannel_call(
     grpc_call_element* elem);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CLIENT_CHANNEL_H */
diff --git a/src/core/ext/filters/client_channel/client_channel_factory.h b/src/core/ext/filters/client_channel/client_channel_factory.h
index cc36a924ee..766ebb9389 100644
--- a/src/core/ext/filters/client_channel/client_channel_factory.h
+++ b/src/core/ext/filters/client_channel/client_channel_factory.h
@@ -27,10 +27,6 @@
 // Channel arg key for client channel factory.
 #define GRPC_ARG_CLIENT_CHANNEL_FACTORY "grpc.client_channel_factory"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_client_channel_factory grpc_client_channel_factory;
 typedef struct grpc_client_channel_factory_vtable
     grpc_client_channel_factory_vtable;
@@ -73,8 +69,4 @@ grpc_channel* grpc_client_channel_factory_create_channel(
 grpc_arg grpc_client_channel_factory_create_channel_arg(
     grpc_client_channel_factory* factory);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CLIENT_CHANNEL_FACTORY_H */
diff --git a/src/core/ext/filters/client_channel/client_channel_plugin.cc b/src/core/ext/filters/client_channel/client_channel_plugin.cc
index 71d4db63dc..ea630d2917 100644
--- a/src/core/ext/filters/client_channel/client_channel_plugin.cc
+++ b/src/core/ext/filters/client_channel/client_channel_plugin.cc
@@ -62,7 +62,7 @@ static bool set_default_host_if_unset(grpc_channel_stack_builder* builder,
   return true;
 }
 
-extern "C" void grpc_client_channel_init(void) {
+void grpc_client_channel_init(void) {
   grpc_lb_policy_registry_init();
   grpc_resolver_registry_init();
   grpc_retry_throttle_map_init();
@@ -77,7 +77,7 @@ extern "C" void grpc_client_channel_init(void) {
   grpc_http_connect_register_handshaker_factory();
 }
 
-extern "C" void grpc_client_channel_shutdown(void) {
+void grpc_client_channel_shutdown(void) {
   grpc_subchannel_index_shutdown();
   grpc_channel_init_shutdown();
   grpc_proxy_mapper_registry_shutdown();
diff --git a/src/core/ext/filters/client_channel/connector.h b/src/core/ext/filters/client_channel/connector.h
index 40f0b723af..d657658d67 100644
--- a/src/core/ext/filters/client_channel/connector.h
+++ b/src/core/ext/filters/client_channel/connector.h
@@ -23,10 +23,6 @@
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/transport/transport.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_connector grpc_connector;
 typedef struct grpc_connector_vtable grpc_connector_vtable;
 
@@ -72,8 +68,4 @@ void grpc_connector_connect(grpc_connector* connector,
 /** Cancel any pending connection */
 void grpc_connector_shutdown(grpc_connector* connector, grpc_error* why);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CONNECTOR_H */
diff --git a/src/core/ext/filters/client_channel/http_connect_handshaker.h b/src/core/ext/filters/client_channel/http_connect_handshaker.h
index 05a23cdba3..928a23dc93 100644
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.h
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.h
@@ -28,15 +28,7 @@
 /// seperated by colons.
 #define GRPC_ARG_HTTP_CONNECT_HEADERS "grpc.http_connect_headers"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /// Registers handshaker factory.
 void grpc_http_connect_register_handshaker_factory();
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HTTP_CONNECT_HANDSHAKER_H */
diff --git a/src/core/ext/filters/client_channel/http_proxy.h b/src/core/ext/filters/client_channel/http_proxy.h
index bdad03def3..34694931d0 100644
--- a/src/core/ext/filters/client_channel/http_proxy.h
+++ b/src/core/ext/filters/client_channel/http_proxy.h
@@ -19,14 +19,6 @@
 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HTTP_PROXY_H
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HTTP_PROXY_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 void grpc_register_http_proxy_mapper();
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HTTP_PROXY_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy.h b/src/core/ext/filters/client_channel/lb_policy.h
index ca1afc42ee..6c241e932a 100644
--- a/src/core/ext/filters/client_channel/lb_policy.h
+++ b/src/core/ext/filters/client_channel/lb_policy.h
@@ -23,10 +23,6 @@
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/transport/connectivity_state.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** A load balancing policy: specified by a vtable and a struct (which
     is expected to be extended to contain some parameters) */
 typedef struct grpc_lb_policy grpc_lb_policy;
@@ -197,8 +193,4 @@ grpc_connectivity_state grpc_lb_policy_check_connectivity_locked(
 void grpc_lb_policy_update_locked(grpc_lb_policy* policy,
                                   const grpc_lb_policy_args* lb_policy_args);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
index abf613a23b..04de7a04df 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h
@@ -21,15 +21,7 @@
 
 #include "src/core/lib/channel/channel_stack.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 extern const grpc_channel_filter grpc_client_load_reporting_filter;
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_CLIENT_LOAD_REPORTING_FILTER_H \
         */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
index 9ed435988f..9a52f297b3 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
@@ -1958,7 +1958,7 @@ static bool maybe_add_client_load_reporting_filter(
   return true;
 }
 
-extern "C" void grpc_lb_policy_grpclb_init() {
+void grpc_lb_policy_grpclb_init() {
   grpc_register_lb_policy(grpc_glb_lb_factory_create());
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
                                    GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
@@ -1966,4 +1966,4 @@ extern "C" void grpc_lb_policy_grpclb_init() {
                                    (void*)&grpc_client_load_reporting_filter);
 }
 
-extern "C" void grpc_lb_policy_grpclb_shutdown() {}
+void grpc_lb_policy_grpclb_shutdown() {}
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
index b6135a4768..0a2edb0e3d 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.h
@@ -21,17 +21,9 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** Returns a load balancing factory for the glb policy, which tries to connect
  * to a load balancing server to decide the next successfully connected
  * subchannel to pick. */
 grpc_lb_policy_factory* grpc_glb_lb_factory_create();
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_GRPCLB_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
index d14def4910..56104b2ec0 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h
@@ -23,10 +23,6 @@
 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/lib/slice/slice_hash_table.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** Create the channel used for communicating with an LB service.
  * Note that an LB *service* may be comprised of several LB *servers*.
  *
@@ -44,9 +40,5 @@ grpc_channel_args* grpc_lb_policy_grpclb_build_lb_channel_args(
     grpc_fake_resolver_response_generator* response_generator,
     const grpc_channel_args* args);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H \
         */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
index ce88cf9ee4..d4b9d06848 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.h
@@ -23,10 +23,6 @@
 
 #include <grpc/impl/codegen/grpc_types.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_grpclb_client_stats grpc_grpclb_client_stats;
 
 typedef struct {
@@ -65,9 +61,5 @@ void grpc_grpclb_client_stats_get_locked(
 void grpc_grpclb_dropped_call_counts_destroy(
     grpc_grpclb_dropped_call_counts* drop_entries);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_GRPCLB_CLIENT_STATS_H \
         */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
index 138012c63a..017c40ec1a 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h
@@ -25,10 +25,6 @@
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h"
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #define GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH 128
 
 typedef grpc_lb_v1_Server_ip_address_t grpc_grpclb_ip_address;
@@ -87,9 +83,5 @@ grpc_millis grpc_grpclb_duration_to_millis(grpc_grpclb_duration* duration_pb);
 void grpc_grpclb_initial_response_destroy(
     grpc_grpclb_initial_response* response);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_GRPCLB_LOAD_BALANCER_API_H \
         */
diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
index 93b5feb86b..9fc7f1a5d1 100644
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
@@ -578,8 +578,8 @@ static grpc_lb_policy_factory* pick_first_lb_factory_create() {
 
 /* Plugin registration */
 
-extern "C" void grpc_lb_policy_pick_first_init() {
+void grpc_lb_policy_pick_first_init() {
   grpc_register_lb_policy(pick_first_lb_factory_create());
 }
 
-extern "C" void grpc_lb_policy_pick_first_shutdown() {}
+void grpc_lb_policy_pick_first_shutdown() {}
diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
index 7f21cc8f3c..2eadd6473d 100644
--- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
@@ -675,8 +675,8 @@ static grpc_lb_policy_factory* round_robin_lb_factory_create() {
 
 /* Plugin registration */
 
-extern "C" void grpc_lb_policy_round_robin_init() {
+void grpc_lb_policy_round_robin_init() {
   grpc_register_lb_policy(round_robin_lb_factory_create());
 }
 
-extern "C" void grpc_lb_policy_round_robin_shutdown() {}
+void grpc_lb_policy_round_robin_shutdown() {}
diff --git a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
index 6221e3694f..0f8cea9347 100644
--- a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
+++ b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
@@ -36,10 +36,6 @@
 // round_robin that could be refactored and moved here.  In a future PR,
 // need to clean this up.
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_lb_subchannel_list grpc_lb_subchannel_list;
 
 typedef struct {
@@ -142,8 +138,4 @@ void grpc_lb_subchannel_list_unref_for_connectivity_watch(
 void grpc_lb_subchannel_list_shutdown_and_unref(
     grpc_lb_subchannel_list* subchannel_list, const char* reason);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy_factory.h b/src/core/ext/filters/client_channel/lb_policy_factory.h
index 8c1efac042..9da231b657 100644
--- a/src/core/ext/filters/client_channel/lb_policy_factory.h
+++ b/src/core/ext/filters/client_channel/lb_policy_factory.h
@@ -29,10 +29,6 @@
 // Channel arg key for grpc_lb_addresses.
 #define GRPC_ARG_LB_ADDRESSES "grpc.lb_addresses"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_lb_policy_factory grpc_lb_policy_factory;
 typedef struct grpc_lb_policy_factory_vtable grpc_lb_policy_factory_vtable;
 
@@ -131,8 +127,4 @@ void grpc_lb_policy_factory_unref(grpc_lb_policy_factory* factory);
 grpc_lb_policy* grpc_lb_policy_factory_create_lb_policy(
     grpc_lb_policy_factory* factory, grpc_lb_policy_args* args);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_FACTORY_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy_registry.h b/src/core/ext/filters/client_channel/lb_policy_registry.h
index b66b4d56bb..5aff79376b 100644
--- a/src/core/ext/filters/client_channel/lb_policy_registry.h
+++ b/src/core/ext/filters/client_channel/lb_policy_registry.h
@@ -22,10 +22,6 @@
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** Initialize the registry and set \a default_factory as the factory to be
  * returned when no name is provided in a lookup */
 void grpc_lb_policy_registry_init(void);
@@ -41,8 +37,4 @@ void grpc_register_lb_policy(grpc_lb_policy_factory* factory);
 grpc_lb_policy* grpc_lb_policy_create(const char* name,
                                       grpc_lb_policy_args* args);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_REGISTRY_H */
diff --git a/src/core/ext/filters/client_channel/parse_address.h b/src/core/ext/filters/client_channel/parse_address.h
index b45859f9a2..ca0a0d18f0 100644
--- a/src/core/ext/filters/client_channel/parse_address.h
+++ b/src/core/ext/filters/client_channel/parse_address.h
@@ -24,10 +24,6 @@
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** Populate \a resolved_addr from \a uri, whose path is expected to contain a
  * unix socket path. Returns true upon success. */
 bool grpc_parse_unix(const grpc_uri* uri, grpc_resolved_address* resolved_addr);
@@ -49,8 +45,4 @@ bool grpc_parse_ipv4_hostport(const char* hostport, grpc_resolved_address* addr,
 bool grpc_parse_ipv6_hostport(const char* hostport, grpc_resolved_address* addr,
                               bool log_errors);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_PARSE_ADDRESS_H */
diff --git a/src/core/ext/filters/client_channel/proxy_mapper.h b/src/core/ext/filters/client_channel/proxy_mapper.h
index d4a3793e8a..ce3e65ee46 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper.h
+++ b/src/core/ext/filters/client_channel/proxy_mapper.h
@@ -25,10 +25,6 @@
 
 #include "src/core/lib/iomgr/resolve_address.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_proxy_mapper grpc_proxy_mapper;
 
 typedef struct {
@@ -73,8 +69,4 @@ bool grpc_proxy_mapper_map_address(grpc_proxy_mapper* mapper,
 
 void grpc_proxy_mapper_destroy(grpc_proxy_mapper* mapper);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_PROXY_MAPPER_H */
diff --git a/src/core/ext/filters/client_channel/proxy_mapper_registry.h b/src/core/ext/filters/client_channel/proxy_mapper_registry.h
index efe1df48a6..2ad6c04e1d 100644
--- a/src/core/ext/filters/client_channel/proxy_mapper_registry.h
+++ b/src/core/ext/filters/client_channel/proxy_mapper_registry.h
@@ -21,10 +21,6 @@
 
 #include "src/core/ext/filters/client_channel/proxy_mapper.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 void grpc_proxy_mapper_registry_init();
 void grpc_proxy_mapper_registry_shutdown();
 
@@ -43,8 +39,4 @@ bool grpc_proxy_mappers_map_address(const grpc_resolved_address* address,
                                     grpc_resolved_address** new_address,
                                     grpc_channel_args** new_args);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_PROXY_MAPPER_REGISTRY_H */
diff --git a/src/core/ext/filters/client_channel/resolver.h b/src/core/ext/filters/client_channel/resolver.h
index 7ff21b4d2c..f6a4af01d6 100644
--- a/src/core/ext/filters/client_channel/resolver.h
+++ b/src/core/ext/filters/client_channel/resolver.h
@@ -22,10 +22,6 @@
 #include "src/core/ext/filters/client_channel/subchannel.h"
 #include "src/core/lib/iomgr/iomgr.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_resolver grpc_resolver;
 typedef struct grpc_resolver_vtable grpc_resolver_vtable;
 
@@ -86,8 +82,4 @@ void grpc_resolver_next_locked(grpc_resolver* resolver,
                                grpc_channel_args** result,
                                grpc_closure* on_complete);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_H */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
index f6990e5a5c..4ec4477c82 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -411,7 +411,7 @@ static grpc_resolver_factory* dns_ares_resolver_factory_create() {
   return &dns_resolver_factory;
 }
 
-extern "C" void grpc_resolver_dns_ares_init(void) {
+void grpc_resolver_dns_ares_init(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
   /* TODO(zyc): Turn on c-ares based resolver by default after the address
      sorter and the CNAME support are added. */
@@ -427,7 +427,7 @@ extern "C" void grpc_resolver_dns_ares_init(void) {
   gpr_free(resolver);
 }
 
-extern "C" void grpc_resolver_dns_ares_shutdown(void) {
+void grpc_resolver_dns_ares_shutdown(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
   if (resolver != nullptr && gpr_stricmp(resolver, "ares") == 0) {
     grpc_ares_cleanup();
@@ -437,8 +437,8 @@ extern "C" void grpc_resolver_dns_ares_shutdown(void) {
 
 #else /* GRPC_ARES == 1 && !defined(GRPC_UV) */
 
-extern "C" void grpc_resolver_dns_ares_init(void) {}
+void grpc_resolver_dns_ares_init(void) {}
 
-extern "C" void grpc_resolver_dns_ares_shutdown(void) {}
+void grpc_resolver_dns_ares_shutdown(void) {}
 
 #endif /* GRPC_ARES == 1 && !defined(GRPC_UV) */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
index 5b5ceef9c4..ba7dad63cf 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h
@@ -23,10 +23,6 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/pollset_set.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_ares_ev_driver grpc_ares_ev_driver;
 
 /* Start \a ev_driver. It will keep working until all IO on its ares_channel is
@@ -52,9 +48,5 @@ void grpc_ares_ev_driver_destroy(grpc_ares_ev_driver* ev_driver);
 /* Shutdown all the grpc_fds used by \a ev_driver */
 void grpc_ares_ev_driver_shutdown(grpc_ares_ev_driver* ev_driver);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_EV_DRIVER_H \
         */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
index 46f2a894df..86d870e0a6 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h
@@ -25,10 +25,6 @@
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_ares_request grpc_ares_request;
 
 /* Asynchronously resolve \a name. Use \a default_port if a port isn't
@@ -67,9 +63,5 @@ grpc_error* grpc_ares_init(void);
    it has been called the same number of times as grpc_ares_init(). */
 void grpc_ares_cleanup(void);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_DNS_C_ARES_GRPC_ARES_WRAPPER_H \
         */
diff --git a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
index deda28a3c1..77698e97aa 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
@@ -281,7 +281,7 @@ static grpc_resolver_factory* dns_resolver_factory_create() {
   return &dns_resolver_factory;
 }
 
-extern "C" void grpc_resolver_dns_native_init(void) {
+void grpc_resolver_dns_native_init(void) {
   char* resolver = gpr_getenv("GRPC_DNS_RESOLVER");
   if (resolver != nullptr && gpr_stricmp(resolver, "native") == 0) {
     gpr_log(GPR_DEBUG, "Using native dns resolver");
@@ -299,4 +299,4 @@ extern "C" void grpc_resolver_dns_native_init(void) {
   gpr_free(resolver);
 }
 
-extern "C" void grpc_resolver_dns_native_shutdown(void) {}
+void grpc_resolver_dns_native_shutdown(void) {}
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
index 74840811d9..fe3ad1403c 100644
--- a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
@@ -250,8 +250,8 @@ static const grpc_resolver_factory_vtable fake_resolver_factory_vtable = {
 static grpc_resolver_factory fake_resolver_factory = {
     &fake_resolver_factory_vtable};
 
-extern "C" void grpc_resolver_fake_init(void) {
+void grpc_resolver_fake_init(void) {
   grpc_register_resolver_type(&fake_resolver_factory);
 }
 
-extern "C" void grpc_resolver_fake_shutdown(void) {}
+void grpc_resolver_fake_shutdown(void) {}
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h
index e2008e948e..a8977e5980 100644
--- a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h
@@ -21,10 +21,6 @@
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/lib/channel/channel_args.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \
   "grpc.fake_resolver.response_generator"
 
@@ -60,9 +56,5 @@ grpc_fake_resolver_response_generator_ref(
 void grpc_fake_resolver_response_generator_unref(
     grpc_fake_resolver_response_generator* generator);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H \
         */
diff --git a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
index 26fd607f59..7d1e283fa3 100644
--- a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
@@ -202,7 +202,7 @@ DECL_FACTORY(unix);
 DECL_FACTORY(ipv4);
 DECL_FACTORY(ipv6);
 
-extern "C" void grpc_resolver_sockaddr_init(void) {
+void grpc_resolver_sockaddr_init(void) {
   grpc_register_resolver_type(&ipv4_resolver_factory);
   grpc_register_resolver_type(&ipv6_resolver_factory);
 #ifdef GRPC_HAVE_UNIX_SOCKET
@@ -210,4 +210,4 @@ extern "C" void grpc_resolver_sockaddr_init(void) {
 #endif
 }
 
-extern "C" void grpc_resolver_sockaddr_shutdown(void) {}
+void grpc_resolver_sockaddr_shutdown(void) {}
diff --git a/src/core/ext/filters/client_channel/resolver_factory.h b/src/core/ext/filters/client_channel/resolver_factory.h
index d73748e916..170ecc0b48 100644
--- a/src/core/ext/filters/client_channel/resolver_factory.h
+++ b/src/core/ext/filters/client_channel/resolver_factory.h
@@ -24,10 +24,6 @@
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/lib/iomgr/pollset_set.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct grpc_resolver_factory grpc_resolver_factory;
 typedef struct grpc_resolver_factory_vtable grpc_resolver_factory_vtable;
 
@@ -69,8 +65,4 @@ grpc_resolver* grpc_resolver_factory_create_resolver(
 char* grpc_resolver_factory_get_default_authority(
     grpc_resolver_factory* factory, grpc_uri* uri);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FACTORY_H */
diff --git a/src/core/ext/filters/client_channel/resolver_registry.h b/src/core/ext/filters/client_channel/resolver_registry.h
index 3eae94afa8..bbd30df8da 100644
--- a/src/core/ext/filters/client_channel/resolver_registry.h
+++ b/src/core/ext/filters/client_channel/resolver_registry.h
@@ -22,10 +22,6 @@
 #include "src/core/ext/filters/client_channel/resolver_factory.h"
 #include "src/core/lib/iomgr/pollset_set.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 void grpc_resolver_registry_init();
 void grpc_resolver_registry_shutdown(void);
 
@@ -69,8 +65,4 @@ char* grpc_get_default_authority(const char* target);
     default prefix if needed. */
 char* grpc_resolver_factory_add_default_prefix_if_needed(const char* target);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_REGISTRY_H */
diff --git a/src/core/ext/filters/client_channel/retry_throttle.h b/src/core/ext/filters/client_channel/retry_throttle.h
index 399383df78..bf99297e98 100644
--- a/src/core/ext/filters/client_channel/retry_throttle.h
+++ b/src/core/ext/filters/client_channel/retry_throttle.h
@@ -21,10 +21,6 @@
 
 #include <stdbool.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /// Tracks retry throttling data for an individual server name.
 typedef struct grpc_server_retry_throttle_data grpc_server_retry_throttle_data;
 
@@ -51,8 +47,4 @@ void grpc_retry_throttle_map_shutdown();
 grpc_server_retry_throttle_data* grpc_retry_throttle_map_get_data_for_server(
     const char* server_name, int max_milli_tokens, int milli_token_ratio);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RETRY_THROTTLE_H */
diff --git a/src/core/ext/filters/client_channel/subchannel.h b/src/core/ext/filters/client_channel/subchannel.h
index e65d043b0b..84d9fa27a1 100644
--- a/src/core/ext/filters/client_channel/subchannel.h
+++ b/src/core/ext/filters/client_channel/subchannel.h
@@ -26,10 +26,6 @@
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/metadata.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 // Channel arg containing a grpc_resolved_address to connect to.
 #define GRPC_ARG_SUBCHANNEL_ADDRESS "grpc.subchannel_address"
 
@@ -179,8 +175,4 @@ const char* grpc_get_subchannel_address_uri_arg(const grpc_channel_args* args);
 /// Caller is responsible for freeing the string.
 grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address* addr);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_H */
diff --git a/src/core/ext/filters/client_channel/subchannel_index.h b/src/core/ext/filters/client_channel/subchannel_index.h
index 19f77833d1..bd160a3b13 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.h
+++ b/src/core/ext/filters/client_channel/subchannel_index.h
@@ -21,10 +21,6 @@
 
 #include "src/core/ext/filters/client_channel/subchannel.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /** \file Provides an index of active subchannels so that they can be
     shared amongst channels */
 
@@ -78,8 +74,4 @@ void grpc_subchannel_index_unref(void);
  * force_creation set. */
 void grpc_subchannel_index_test_only_set_force_creation(bool force_creation);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INDEX_H */
diff --git a/src/core/ext/filters/client_channel/uri_parser.h b/src/core/ext/filters/client_channel/uri_parser.h
index 29f61f09ae..24ff06c0b5 100644
--- a/src/core/ext/filters/client_channel/uri_parser.h
+++ b/src/core/ext/filters/client_channel/uri_parser.h
@@ -22,10 +22,6 @@
 #include <stddef.h>
 #include "src/core/lib/iomgr/exec_ctx.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 typedef struct {
   char* scheme;
   char* authority;
@@ -50,8 +46,4 @@ const char* grpc_uri_get_query_arg(const grpc_uri* uri, const char* key);
 /** destroy a uri */
 void grpc_uri_destroy(grpc_uri* uri);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_URI_PARSER_H */