Make CommandBuffer::Flush asynchronous, and add CommandBuffer::FlushSync with former semantics.

chrome/renderer/command_buffer_proxy.h

 // Copyright (c) 2009 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 CHROME_RENDERER_COMMAND_BUFFER_PROXY_H_
 #define CHROME_RENDERER_COMMAND_BUFFER_PROXY_H_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 29 matching lines @@
   // IPC::Channel::Listener implementation:
   virtual bool OnMessageReceived(const IPC::Message& message);
   virtual void OnChannelError();
 
   int route_id() const { return route_id_; }
 
   // CommandBuffer implementation:
   virtual bool Initialize(int32 size);
   virtual gpu::Buffer GetRingBuffer();
   virtual State GetState();
-  virtual State Flush(int32 put_offset);
+  virtual void Flush(int32 put_offset);
+  virtual State FlushSync(int32 put_offset);
   virtual void SetGetOffset(int32 get_offset);
   virtual int32 CreateTransferBuffer(size_t size);
   virtual void DestroyTransferBuffer(int32 id);
   virtual gpu::Buffer GetTransferBuffer(int32 handle);
   virtual void SetToken(int32 token);
   virtual void SetParseError(gpu::error::Error error);
   virtual void OnSwapBuffers();
 
   // Set a callback that will be invoked when the SwapBuffers call has been
   // issued.
@@ skipping 55 matching lines @@
   scoped_ptr<Task> notify_repaint_task_;
 
   scoped_ptr<Callback0::Type> swap_buffers_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CommandBufferProxy);
 };
 
 #endif  // ENABLE_GPU
 
 #endif  // CHROME_RENDERER_COMMAND_BUFFER_PROXY_H_