Read compositor VSync information from platform, when possible

content/browser/compositor/gpu_browser_compositor_output_surface.h

 // Copyright 2014 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_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 #define CONTENT_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 
 #include "content/browser/compositor/browser_compositor_output_surface.h"
 
+namespace ui {
+class CompositorVSyncManager;
+}
+
 namespace content {
 
 // Adapts a WebGraphicsContext3DCommandBufferImpl into a
 // cc::OutputSurface that also handles vsync parameter updates
 // arriving from the GPU process.
 class GpuBrowserCompositorOutputSurface
     : public BrowserCompositorOutputSurface {
  public:
   GpuBrowserCompositorOutputSurface(
       const scoped_refptr<ContextProviderCommandBuffer>& context,
       int surface_id,
       IDMap<BrowserCompositorOutputSurface>* output_surface_map,
-      base::MessageLoopProxy* compositor_message_loop,
-      base::WeakPtr<ui::Compositor> compositor);
+      const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager);
 
   virtual ~GpuBrowserCompositorOutputSurface();
 
  private:
   // cc::OutputSurface implementation.
   virtual void SwapBuffers(cc::CompositorFrame* frame) OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(GpuBrowserCompositorOutputSurface);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_