cc: Measure compositor timing with finer granularity

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 248e6aea88f1be109316eadce45fa448b36b78ad..533c4906a011be0c0898e7f2d9d5e7fcb2170bea 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -912,6 +912,8 @@ void ThreadProxy::ScheduledActionCommit() {
     impl().commit_completion_event = NULL;
   }
 
+  impl().scheduler->DidCommit();
+
   // Delay this step until afer the main thread has been released as it's
   // often a good bit of work to update the tree and prepare the new frame.
   impl().layer_tree_host_impl->CommitComplete();
@@ -1238,6 +1240,11 @@ void ThreadProxy::DidActivateSyncTree() {
       impl().last_begin_main_frame_args;
 }
 
+void ThreadProxy::WillPrepareTiles() {
+  DCHECK(IsImplThread());
+  impl().scheduler->WillPrepareTiles();
+}
+
 void ThreadProxy::DidPrepareTiles() {
   DCHECK(IsImplThread());
   impl().scheduler->DidPrepareTiles();