cc: Add main frame timing info to frame timing tracker.

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 e45b182f301c1119717058896d624fc0f3b77a13..5b5a709b04bfc565bcdc21cfd1e717b57624654c 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -837,4 +837,9 @@ void SingleThreadProxy::SendBeginFramesToChildren(const BeginFrameArgs& args) {
   layer_tree_host_->SendBeginFramesToChildren(args);
 }
 
+base::TimeTicks SingleThreadProxy::GetNextBeginImplFrameTimeIfRequested()
+    const {
+  return scheduler_on_impl_thread_->NextBeginImplFrameTimeIfRequested();
+}
+
 }  // namespace cc