Dynamically set CAOpenGLLAyer to be asynchronous

content/browser/renderer_host/render_widget_host_view_mac.h

Index: content/browser/renderer_host/render_widget_host_view_mac.h
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index 2c3d44ffffee265d0813f9ced4f651e46d4daef3..e1416331a55436eebc65f44105720cda45ea4a4d 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -435,6 +435,11 @@ class RenderWidgetHostViewMac : public RenderWidgetHostViewBase,
   scoped_ptr<CompositingIOSurfaceMac> compositing_iosurface_;
   scoped_refptr<CompositingIOSurfaceContext> compositing_iosurface_context_;
 
+  // Timer used to dynamically transition the compositing layer in and out of
+  // asynchronous mode.
+  base::DelayTimer<RenderWidgetHostViewMac>
+      compositing_iosurface_layer_async_timer_;
+
   // This holds the current software compositing framebuffer, if any.
   scoped_ptr<SoftwareFrameManager> software_frame_manager_;
 
@@ -512,6 +517,10 @@ class RenderWidgetHostViewMac : public RenderWidgetHostViewBase,
   // Called when a software DIB is received.
   void GotSoftwareFrame();
 
+  // Called if it has been a quarter-second since a GPU SwapBuffers has been
+  // received. In this case, switch from polling for frames to pushing them.
+  void TimerSinceGotAcceleratedFrameFired();
+
   void OnPluginFocusChanged(bool focused, int plugin_id);
   void OnStartPluginIme();