Mac gpu: on gpu<->nongpu transitions, make sure to not show uninitialized memory

chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h

Index: chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h
diff --git a/chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h b/chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h
index 1f5e0a7f1fa0dba58e276c687dbf77a8a4922fce..a03a5c49a5e4ea8ff45832bc36197e9b9dbe7572 100644
--- a/chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h
+++ b/chrome/browser/renderer_host/accelerated_surface_container_manager_mac.h
@@ -46,7 +46,7 @@ class AcceleratedSurfaceContainerManagerMac {
   }
 
   // Informs the manager if gpu rendering is active.
-  void set_gpu_rendering_active(bool active) { gpu_rendering_active_ = active; }
+  void set_gpu_rendering_active(bool active);
 
   // Sets the size and backing store of the plugin instance.  There are two
   // versions: the IOSurface version is used on systems where the IOSurface
@@ -76,6 +76,9 @@ class AcceleratedSurfaceContainerManagerMac {
   // Notifies a surface that it has been painted to.
   void SetSurfaceWasPaintedTo(gfx::PluginWindowHandle id, uint64 surface_id);
 
+  // Notifies the root container that its surface is invalid.
+  void SetRootSurfaceInvalid();
+
   // Returns if a given surface should be shown.
   bool SurfaceShouldBeVisible(gfx::PluginWindowHandle id) const;
  private: