Merge pull request #17086 from markdroth/channelz_subchannel_cleanup

Record subchannel calls started as part of creating subchannel call.

src/core/ext/filters/client_channel/client_channel.cc

@@ -2715,11 +2715,6 @@ static void create_subchannel_call(grpc_call_element* elem, grpc_error* error) {
     new_error = grpc_error_add_child(new_error, error);
     pending_batches_fail(elem, new_error, true /* yield_call_combiner */);
   } else {
-    grpc_core::channelz::SubchannelNode* channelz_subchannel =
-        calld->pick.connected_subchannel->channelz_subchannel();
-    if (channelz_subchannel != nullptr) {
-      channelz_subchannel->RecordCallStarted();
-    }
     if (parent_data_size > 0) {
       subchannel_call_retry_state* retry_state =
           static_cast<subchannel_call_retry_state*>(

src/core/ext/filters/client_channel/subchannel.cc

@@ -1128,6 +1128,9 @@ grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
     return error;
   }
   grpc_call_stack_set_pollset_or_pollset_set(callstk, args.pollent);
+  if (channelz_subchannel_ != nullptr) {
+    channelz_subchannel_->RecordCallStarted();
+  }
   return GRPC_ERROR_NONE;
 }