Add IPC allowing GPU process to tell browser process to temporarily drop a front buffer.

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_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 91 matching lines @@
   void SendResizeView(const gfx::Size& size);
 
   // Whether or not we should execute more commands.
   void SetScheduled(bool is_scheduled);
 
   void DeferToFence(base::Closure task);
 
   // Make the surface's context current.
   bool MakeCurrent();
 
+  void Suspend();
+
  private:
   gpu::GpuScheduler* Scheduler();
   gpu::gles2::GLES2Decoder* Decoder();
 
   // IPC::Message handlers.
   void OnNewSurfaceACK(uint64 surface_handle, TransportDIB::Handle shm_handle);
   void OnBuffersSwappedACK();
   void OnPostSubBufferACK();
   void OnResizeViewACK();
 
@@ skipping 42 matching lines @@
  private:
   scoped_ptr<ImageTransportHelper> helper_;
   gfx::Size new_size_;
 
   DISALLOW_COPY_AND_ASSIGN(PassThroughImageTransportSurface);
 };
 
 #endif  // defined(ENABLE_GPU)
 
 #endif  // CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_H_