Provide a vsync notification to the renderer

content/port/browser/render_widget_host_view_port.h

Index: content/port/browser/render_widget_host_view_port.h
diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index 9fbdeccdf86542cb7e8bca9520fa14774b8e0bde..d7540eac639d430ac6d544ce669dcfdfa8e14730 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -181,6 +181,10 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
       const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params_in_pixel,
       int gpu_host_id) = 0;
 
+  // Request a periodic vsync signal notification from the View. The signal will
+  // be delivered until explicitly disabled.
+  virtual void EnableVSyncNotification(bool enable) {}
+
   // Release the accelerated surface temporarily. It will be recreated on the
   // next swap buffers or post sub buffer.
   virtual void AcceleratedSurfaceSuspend() = 0;