sync compositor: Signal async frame on IO thread

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 2012 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1186 matching lines @@
   AddFilter(notification_message_filter_.get());
 
   AddFilter(new GamepadBrowserMessageFilter());
   AddFilter(new ProfilerMessageFilter(PROCESS_TYPE_RENDERER));
   AddFilter(new HistogramMessageFilter());
   AddFilter(new MemoryMessageFilter(this));
   AddFilter(new PushMessagingMessageFilter(
       GetID(), storage_partition_impl_->GetServiceWorkerContext()));
 #if defined(OS_ANDROID)
   AddFilter(new ScreenOrientationMessageFilterAndroid());
+  synchronous_compositor_filter_ = new SynchronousCompositorObserver(GetID());
+  AddFilter(synchronous_compositor_filter_.get());
 #endif
 }
 
 void RenderProcessHostImpl::RegisterMojoInterfaces() {
   std::unique_ptr<service_manager::InterfaceRegistry> registry(
       new service_manager::InterfaceRegistry);
 
   channel_->AddAssociatedInterface(
       base::Bind(&RenderProcessHostImpl::OnRouteProviderRequest,
                  base::Unretained(this)));
@@ skipping 1784 matching lines @@
   bad_message::ReceivedBadMessage(render_process_id,
                                   bad_message::RPH_MOJO_PROCESS_ERROR);
 }
 
 void RenderProcessHostImpl::CreateURLLoaderFactory(
     mojo::InterfaceRequest<mojom::URLLoaderFactory> request) {
   URLLoaderFactoryImpl::Create(resource_message_filter_, std::move(request));
 }
 
 }  // namespace content