not for commit/review (thread cost tracker)

cc/debug/frame_timing_cost_tracker.h

Index: cc/debug/frame_timing_cost_tracker.h
diff --git a/cc/debug/frame_timing_cost_tracker.h b/cc/debug/frame_timing_cost_tracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..d8d4cb237f785f1a7ed95ef7bd71986be689f24d
--- /dev/null
+++ b/cc/debug/frame_timing_cost_tracker.h
@@ -0,0 +1,31 @@
+// Copyright 2014 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.
+
+#ifndef CC_DEBUG_FRAME_TIMING_COST_TRACKER_H_
+#define CC_DEBUG_FRAME_TIMING_COST_TRACKER_H_
+
+#include "cc/debug/worker_thread_cost_tracker.h"
+
+namespace cc {
+
+class FrameTimingCostTracker {
+ public:
+  FrameTimingCostTracker();
+  ~FrameTimingCostTracker();
+
+  void Start(int source_frame_number);
+  void Stop();
+
+  base::TimeDelta GetTotalCost();
+  void ResetCost();
+
+  WorkerThreadCostTracker* GetWorkerThreadCostTracker();
+
+ private:
+  WorkerThreadCostTracker worker_thread_cost_tracker_;
+};
+
+}  // namespace cc
+
+#endif  // CC_DEBUG_FRAME_TIMING_COST_TRACKER_H_