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 476b86dce8310bb235402a50a67bab4137f8fca5..f428c74cbb1e1598bbfbf8a3bd4557c6a74efdac 100644
--- a/content/public/browser/android/synchronous_compositor.h
+++ b/content/public/browser/android/synchronous_compositor.h
@@ -14,6 +14,7 @@
 class SkCanvas;
 
 namespace cc {
+class BeginFrameArgs;
 class CompositorFrame;
 class CompositorFrameAck;
 }
@@ -87,6 +88,14 @@ class CONTENT_EXPORT SynchronousCompositor {
   // SynchronousCompositorClient::GetTotalRootLayerScrollOffset).
   virtual void DidChangeRootLayerScrollOffset() = 0;
 
+  // Called by the embedder to notify that the compositor is active. The
+  // compositor won't ask for vsyncs when it's active. NOTE: The compositor
+  // starts off as inactive and needs a SetActive(true) call to begin.
+  virtual void SetIsActive(bool is_active) = 0;
+
+  // VSync callback from the platform.
+  virtual void SendBeginFrame(cc::BeginFrameArgs args) = 0;

[boliu, 2015/02/11 02:28:14]

No need to expose this to public interface. It's only called from content code.
Also const& args?

+
  protected:
   virtual ~SynchronousCompositor() {}
 };