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

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 770d9b0abd4bbaad26d8e1fd9b7434ab0e3a7c75..54308acc9f9005e513b93185bb25c0e6e00545c7 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -513,7 +513,7 @@ void SingleThreadProxy::CompositeImmediately(base::TimeTicks frame_begin_time) {
   {
     BeginFrameArgs begin_frame_args(BeginFrameArgs::Create(
         BEGINFRAME_FROM_HERE, frame_begin_time, base::TimeTicks(),
-        BeginFrameArgs::DefaultInterval(), BeginFrameArgs::SYNCHRONOUS));
+        BeginFrameArgs::DefaultInterval(), BeginFrameArgs::NORMAL));
     DoBeginMainFrame(begin_frame_args);
     DoCommit();
 
@@ -802,6 +802,11 @@ void SingleThreadProxy::ScheduledActionPrepareTiles() {
   layer_tree_host_impl_->PrepareTiles();
 }
 
+void SingleThreadProxy::ScheduledActionInvalidateOutputSurface() {
+  DCHECK(layer_tree_host_impl_->output_surface());
+  layer_tree_host_impl_->output_surface()->Invalidate();
+}
+
 void SingleThreadProxy::DidAnticipatedDrawTimeChange(base::TimeTicks time) {
 }