Merge pull request #17442 from markdroth/client_channel_pick_init

Remove unnecessary initialization of fields in PickState.

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

@@ -570,12 +570,6 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) {
     } else {
       grpc_error* error = GRPC_ERROR_NONE;
       grpc_core::LoadBalancingPolicy::PickState pick_state;
-      pick_state.initial_metadata = nullptr;
-      pick_state.initial_metadata_flags = 0;
-      pick_state.on_complete = nullptr;
-      memset(&pick_state.subchannel_call_context, 0,
-             sizeof(pick_state.subchannel_call_context));
-      pick_state.user_data = nullptr;
       // Pick must return synchronously, because pick_state.on_complete is null.
       GPR_ASSERT(chand->lb_policy->PickLocked(&pick_state, &error));
       if (pick_state.connected_subchannel != nullptr) {