Provide a vsync notification to the renderer

content/port/browser/render_widget_host_view_port.h

 // Copyright (c) 2012 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 CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 #define CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 
 #include "base/callback.h"
 #include "base/process_util.h"
 #include "base/string16.h"
@@ skipping 163 matching lines @@
   // enforced; this case is currently used for accelerated plugins.
   virtual void AcceleratedSurfaceBuffersSwapped(
       const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params_in_pixel,
       int gpu_host_id) = 0;
   // Similar to above, except |params.(x|y|width|height)| define the region
   // of the surface that changed.
   virtual void AcceleratedSurfacePostSubBuffer(
       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;
 
   // Return true if the view has an accelerated surface that contains the last
   // presented frame for the view. If |desired_size| is non-empty, true is
   // returned only if the accelerated surface size matches.
   virtual bool HasAcceleratedSurface(const gfx::Size& desired_size) = 0;
 
 #if defined(OS_MACOSX)
@@ skipping 92 matching lines @@
   virtual BrowserAccessibilityManager*
       GetBrowserAccessibilityManager() const = 0;
   virtual void OnAccessibilityNotifications(
       const std::vector<AccessibilityHostMsg_NotificationParams>& params) {
   }
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_