Mac: Correctly show/hide compositor on navigations.

chrome/browser/renderer_host/render_widget_host_view.h

 // Copyright (c) 2010 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_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_H_
 #pragma once
 
 #if defined(OS_MACOSX)
 #include <OpenGL/OpenGL.h>
@@ skipping 200 matching lines @@
       int32 width,
       int32 height,
       uint64 io_surface_identifier) = 0;
   virtual void AcceleratedSurfaceSetTransportDIB(
       gfx::PluginWindowHandle window,
       int32 width,
       int32 height,
       TransportDIB::Handle transport_dib) = 0;
   virtual void AcceleratedSurfaceBuffersSwapped(
       gfx::PluginWindowHandle window) = 0;
+  virtual void GpuRenderingStateDidChange() = 0;
 #endif
 
 #if defined(TOOLKIT_USES_GTK)
   virtual void CreatePluginContainer(gfx::PluginWindowHandle id) = 0;
   virtual void DestroyPluginContainer(gfx::PluginWindowHandle id) = 0;
 #endif
 
   // Toggles visual muting of the render view area. This is on when a
   // constrained window is showing.
   virtual void SetVisuallyDeemphasized(bool deemphasized) = 0;
@@ skipping 29 matching lines @@
 
   // A custom background to paint behind the web content. This will be tiled
   // horizontally. Can be null, in which case we fall back to painting white.
   SkBitmap background_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostView);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_H_