Only send the FrameSinkId to client when it is necessary

content/renderer/mus/renderer_window_tree_client.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/mus/renderer_window_tree_client.h"
 
 #include <map>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 59 matching lines @@
 
 RendererWindowTreeClient::~RendererWindowTreeClient() {
   g_connections.Get().erase(routing_id_);
 }
 
 void RendererWindowTreeClient::RequestCompositorFrameSinkInternal(
     scoped_refptr<cc::ContextProvider> context_provider,
     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
     const CompositorFrameSinkCallback& callback) {
   std::unique_ptr<ui::ClientCompositorFrameSinkBinding> frame_sink_binding;
+  bool enable_surface_synchronization =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          cc::switches::kEnableSurfaceSynchronization);
   auto frame_sink = ui::ClientCompositorFrameSink::Create(
-      frame_sink_id_, std::move(context_provider), gpu_memory_buffer_manager,
-      &frame_sink_binding);
+      std::move(context_provider), gpu_memory_buffer_manager,
+      &frame_sink_binding, enable_surface_synchronization);
   tree_->AttachCompositorFrameSink(
       root_window_id_, frame_sink_binding->TakeFrameSinkRequest(),
       mojo::MakeProxy(frame_sink_binding->TakeFrameSinkClient()));
   callback.Run(std::move(frame_sink));
 }
 
 void RendererWindowTreeClient::DestroySelf() {
   delete this;
 }
 
@@ skipping 164 matching lines @@
                                                  bool success) {}
 
 void RendererWindowTreeClient::RequestClose(uint32_t window_id) {}
 
 void RendererWindowTreeClient::GetWindowManager(
     mojo::AssociatedInterfaceRequest<ui::mojom::WindowManager> internal) {
   NOTREACHED();
 }
 
 }  // namespace content