Pipe impl_latency_takes_priority_ to the RenderScheduler.

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 91816b9c057daff0b81c3f6b2fb1153cfdab537b..15fa72081078046458837698b380da9ab6d847f7 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -610,7 +610,10 @@ 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::NORMAL));
+      BeginFrameArgs::DefaultInterval(), BeginFrameArgs::NORMAL,
+      scheduler_on_impl_thread_
+          ? scheduler_on_impl_thread_->MainThreadOnCriticalPath()

[Sami, 2015/06/08 11:47:53]

I think this should default to true when we are using the single threaded
compositor. The compositor can't really do anything before the BeginFrame
completes.

[alex clarke (OOO till 29th), 2015/06/08 16:58:07]

Done.

+          : false));
 
   // Start the impl frame.
   {