Update from https://crrev.com/305340

cc/trees/layer_tree_host_client.h

 // Copyright 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 CC_TREES_LAYER_TREE_HOST_CLIENT_H_
 #define CC_TREES_LAYER_TREE_HOST_CLIENT_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
@@ skipping 27 matching lines @@
   // call LayerTreeHost::SetOutputSurface.  If fallback is true, it should
   // attempt to create an OutputSurface that is guaranteed to initialize
   // correctly.
   virtual void RequestNewOutputSurface(bool fallback) = 0;
   virtual void DidInitializeOutputSurface() = 0;
   virtual void WillCommit() = 0;
   virtual void DidCommit() = 0;
   virtual void DidCommitAndDrawFrame() = 0;
   virtual void DidCompleteSwapBuffers() = 0;
 
+  // TODO(simonhong): Makes this to pure virtual function when client
+  // implementation is ready.
+  virtual void SendBeginFramesToChildren(const BeginFrameArgs& args) {}
+
   // Requests that the client insert a rate limiting token in the shared main
   // thread context's command stream that will block if the context gets too far
   // ahead of the compositor's command stream. Only needed if the tree contains
   // a TextureLayer that calls SetRateLimitContext(true).
   virtual void RateLimitSharedMainThreadContext() {}
 
   // This hook is for testing.
   virtual void DidFailToInitializeOutputSurface() {}
 
  protected:
   virtual ~LayerTreeHostClient() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_CLIENT_H_