Delete background tab IOSurfaces on Mac.

content/browser/renderer_host/render_process_host_impl.h

Index: content/browser/renderer_host/render_process_host_impl.h
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index 09e861d16d3eef2c3b10507ccd62f820d9d3fb59..ef7e4338d39965f9cc426fccb6e93fddaa01926f 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -63,9 +63,9 @@ class CONTENT_EXPORT RenderProcessHostImpl
   virtual void CancelResourceRequests(int render_widget_id) OVERRIDE;
   virtual void SimulateSwapOutACK(
       const ViewMsg_SwapOut_Params& params) OVERRIDE;
-  virtual bool WaitForUpdateMsg(int render_widget_id,
-                                const base::TimeDelta& max_delay,
-                                IPC::Message* msg) OVERRIDE;
+  virtual bool WaitForBackingStoreMsg(int render_widget_id,
+                                      const base::TimeDelta& max_delay,
+                                      IPC::Message* msg) OVERRIDE;
   virtual void ReceivedBadMessage() OVERRIDE;
   virtual void WidgetRestored() OVERRIDE;
   virtual void WidgetHidden() OVERRIDE;
@@ -162,6 +162,12 @@ class CONTENT_EXPORT RenderProcessHostImpl
   void OnRevealFolderInOS(const FilePath& path);
   void OnSavedPageAsMHTML(int job_id, int64 mhtml_file_size);
 
+  // CompositorSurfaceBuffersSwapped handler when there's no RWH.
+  void OnCompositorSurfaceBuffersSwappedNoHost(int32 surface_id,
+                                               uint64 surface_handle,
+                                               int32 route_id,
+                                               int32 gpu_process_host_id);
+
   // Generates a command line to be used to spawn a renderer and appends the
   // results to |*command_line|.
   void AppendRendererCommandLine(CommandLine* command_line) const;