Add support to delay sending SwapbufferAck as needed.

content/common/gpu/image_transport_surface.h

 // Copyright (c) 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.
 
 #ifndef CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_H_
 #define CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 182 matching lines @@
   void SetLatencyInfo(
       const std::vector<ui::LatencyInfo>& latency_info) override;
   void WakeUpGpu() override;
 
  protected:
   ~PassThroughImageTransportSurface() override;
 
   // If updated vsync parameters can be determined, send this information to
   // the browser.
   virtual void SendVSyncUpdateIfAvailable();
+  void SwapBuffersCallBack();
 
   ImageTransportHelper* GetHelper() { return helper_.get(); }
 
  private:
   scoped_ptr<ImageTransportHelper> helper_;
   bool did_set_swap_interval_;
   std::vector<ui::LatencyInfo> latency_info_;
 
   DISALLOW_COPY_AND_ASSIGN(PassThroughImageTransportSurface);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_H_