Chromium implementation of discardBackbuffer WebGraphicsContext3D extension.

content/common/gpu/client/command_buffer_proxy.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_CLIENT_COMMAND_BUFFER_PROXY_H_
 #define CONTENT_COMMON_GPU_CLIENT_COMMAND_BUFFER_PROXY_H_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 56 matching lines @@
   virtual void SetContextLostReason(
       gpu::error::ContextLostReason reason) OVERRIDE;
 
   // Invoke the task when the channel has been flushed. Takes care of deleting
   // the task whether the echo succeeds or not.
   bool Echo(const base::Closure& callback);
 
   // Sends an IPC message with the new state of surface visibility.
   bool SetSurfaceVisible(bool visible);
 
+  bool DiscardBackbuffer();
+  bool EnsureBackbuffer();
+
   // Register a callback to invoke whenever we recieve a new memory allocation.
   void SetMemoryAllocationChangedCallback(
       const base::Callback<void(const GpuMemoryAllocationForRenderer&)>&
           callback);
 
   // Reparent a command buffer. TODO(apatrick): going forward, the notion of
   // the parent / child relationship between command buffers is going away in
   // favor of the notion of surfaces that can be drawn to in one command buffer
   // and bound as a texture in any other.
   virtual bool SetParent(CommandBufferProxy* parent_command_buffer,
@@ skipping 75 matching lines @@
       memory_allocation_changed_callback_;
 
   GpuConsoleMessageCallback console_message_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CommandBufferProxy);
 };
 
 #endif  // ENABLE_GPU
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_COMMAND_BUFFER_PROXY_H_