Trace main thread commit in flow events.

cc/trees/layer_tree_host.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 1282 matching lines @@
   proxy_->SetAuthoritativeVSyncInterval(interval);
 }
 
 void LayerTreeHost::RecordFrameTimingEvents(
     scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
     scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events) {
   client_->RecordFrameTimingEvents(composite_events.Pass(),
                                    main_frame_events.Pass());
 }
 
+void LayerTreeHost::OnCommitForSwapPromises() {

[brianderson, 2015/06/17 18:18:04]

Can you group this with the other swap promise logic near line 1266?

Also, instead of making this a public method can you make it protected and call
it from LayerTreeHost::WillCommit?

+  for (auto* swap_promise : swap_promise_list_)
+    swap_promise->OnCommit();
+}
+
 }  // namespace cc