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

content/public/browser/android/synchronous_compositor.h

 // Copyright 2013 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_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_
 #define CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_
 
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "gpu/command_buffer/service/in_process_command_buffer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
 class SkCanvas;
 
 namespace cc {
+class BeginFrameArgs;
 class CompositorFrame;
 class CompositorFrameAck;
 }
 
 namespace gfx {
 class Transform;
 };
 
 namespace gpu {
 class GLInProcessContext;
@@ skipping 53 matching lines @@
   virtual bool DemandDrawSw(SkCanvas* canvas) = 0;
 
   // Set the memory limit policy of this compositor.
   virtual void SetMemoryPolicy(size_t bytes_limit) = 0;
 
   // Should be called by the embedder after the embedder had modified the
   // scroll offset of the root layer (as returned by
   // 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

[hush (inactive), 2015/02/11 20:43:40]

do you mean 
The compositor won't ask for vsyncs when it's inactive?

[sunnyps, 2015/04/01 19:53:01]

Done.

+  // 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;
+
  protected:
   virtual ~SynchronousCompositor() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_