cc: Make scheduling be driven by vsync for android webview.

content/public/browser/android/synchronous_compositor.h

Index: content/public/browser/android/synchronous_compositor.h
diff --git a/content/public/browser/android/synchronous_compositor.h b/content/public/browser/android/synchronous_compositor.h
index 7171798eb74498a1be01f3f60d635e9aa2d38234..bf5d2f78a4d6dbc02cdaeb34f8eeddc9d2fbe0b6 100644
--- a/content/public/browser/android/synchronous_compositor.h
+++ b/content/public/browser/android/synchronous_compositor.h
@@ -87,6 +87,10 @@ class CONTENT_EXPORT SynchronousCompositor {
   // SynchronousCompositorClient::GetTotalRootLayerScrollOffset).
   virtual void DidChangeRootLayerScrollOffset() = 0;
 
+  // VSync callback from the platform.
+  virtual void OnVSync(base::TimeTicks frame_time, 
+      base::TimeDelta vsync_period) = 0;
+
  protected:
   virtual ~SynchronousCompositor() {}
 };