cc: Release main thread earlier

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 a1ce1b557c987fa121498a7acafb657db9b04655..e15ad6de3031c8308f055a0eb45ba744660d9908 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -1022,15 +1022,8 @@ void ThreadProxy::ScheduledActionCommit() {
   layer_tree_host_impl_->BeginCommit();
   layer_tree_host()->BeginCommitOnImplThread(layer_tree_host_impl_.get());
   layer_tree_host()->FinishCommitOnImplThread(layer_tree_host_impl_.get());
-  layer_tree_host_impl_->CommitComplete();
   inside_commit_ = false;

[enne (OOO), 2014/01/15 00:36:04]

This variable is a little bit weird.  It's only read on the main thread, so it
needs to get updated before the lock is released.

Maybe it needs to be renamed for clarity, since in some ways the commit isn't
done for the compositor thread at this point.

[brianderson, 2014/01/15 00:59:38]

main_thread_inside_commit_?

[enne (OOO), 2014/01/15 01:21:49]

Done.

 
-  SetInputThrottledUntilCommitOnImplThread(false);
-
-  UpdateBackgroundAnimateTicking();
-
-  next_frame_is_newly_committed_frame_on_impl_thread_ = true;
-
   if (layer_tree_host()->settings().impl_side_painting &&
       commit_waits_for_activation_) {
     // For some layer types in impl-side painting, the commit is held until
@@ -1045,6 +1038,15 @@ void ThreadProxy::ScheduledActionCommit() {
     commit_completion_event_on_impl_thread_ = NULL;
   }
 
+  // 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.
+  layer_tree_host_impl_->CommitComplete();
+
+  SetInputThrottledUntilCommitOnImplThread(false);
+
+  UpdateBackgroundAnimateTicking();
+
+  next_frame_is_newly_committed_frame_on_impl_thread_ = true;
   commit_waits_for_activation_ = false;
 
   commit_complete_time_ = base::TimeTicks::HighResNow();