Refactor how surfaces are acquired for GPU compositing.

chrome/browser/renderer_host/render_widget_host_view_mac.h

 // Copyright (c) 2006-2008 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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #pragma once
 
 #import <Cocoa/Cocoa.h>
 #import <QuartzCore/CALayer.h>
@@ skipping 244 matching lines @@
       int32 width,
       int32 height,
       TransportDIB::Handle transport_dib);
   virtual void AcceleratedSurfaceBuffersSwapped(
       gfx::PluginWindowHandle window,
       uint64 surface_id,
       int32 renderer_id,
       int32 route_id,
       uint64 swap_buffers_count);
   virtual void GpuRenderingStateDidChange();
+
+  virtual gfx::PluginWindowHandle AcquireCompositingSurface();
+  virtual void ReleaseCompositingSurface(gfx::PluginWindowHandle surface);
+
   void DrawAcceleratedSurfaceInstance(
       CGLContextObj context,
       gfx::PluginWindowHandle plugin_handle,
       NSSize size);
   // Forces the textures associated with any accelerated plugin instances
   // to be reloaded.
   void ForceTextureReload();
 
   virtual void SetVisuallyDeemphasized(const SkColor* color, bool animate);
 
@@ skipping 97 matching lines @@
 
   // When rendering transitions from gpu to software, the gpu widget can't be
   // hidden until the software backing store has been updated. This variable is
   // set when the gpu widget needs to be hidden once a paint is completed.
   bool needs_gpu_visibility_update_after_repaint_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_