Chromium implementation of discardBackbuffer WebGraphicsContext3D extension.

webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.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 WEBKIT_GPU_WEBGRAPHICSCONTEXT3D_IN_PROCESS_COMMAND_BUFFER_IMPL_H_
 #define WEBKIT_GPU_WEBGRAPHICSCONTEXT3D_IN_PROCESS_COMMAND_BUFFER_IMPL_H_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 406 matching lines @@
       WGC3Dsizei width,
       WGC3Dsizei height,
       WGC3Denum format,
       WGC3Denum type,
       WGC3Denum access);
   virtual void unmapTexSubImage2DCHROMIUM(const void*);
 
   virtual void setVisibilityCHROMIUM(bool visible);
 
   virtual void setMemoryAllocationChangedCallbackCHROMIUM(
-      WebGraphicsMemoryAllocationChangedCallbackCHROMIUM* callback) { }
+      WebGraphicsMemoryAllocationChangedCallbackCHROMIUM* callback);
+
+  virtual void discardFramebufferEXT(WGC3Denum target,
+                                     WGC3Dsizei numAttachments,
+                                     const WGC3Denum* attachments);
+  virtual void ensureFramebufferCHROMIUM();
 
   virtual void copyTextureToParentTextureCHROMIUM(
       WebGLId texture, WebGLId parentTexture);
 
   virtual void rateLimitOffscreenContextCHROMIUM();
 
   virtual WebKit::WebString getRequestableExtensionsCHROMIUM();
   virtual void requestExtensionCHROMIUM(const char*);
 
   virtual void blitFramebufferCHROMIUM(
@@ skipping 70 matching lines @@
                       unsigned int width,
                       unsigned int height);
 #endif
 };
 
 }  // namespace gpu
 }  // namespace webkit
 
 #endif  // defined(ENABLE_GPU)
 #endif  // WEBKIT_GPU_WEBGRAPHICSCONTEXT3D_IN_PROCESS_COMMAND_BUFFER_IMPL_H_