gfx: Add FrameTime and DisplayTime classes

cc/debug/frame_rate_counter.h

 // Copyright 2012 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_RATE_COUNTER_H_
 #define CC_DEBUG_FRAME_RATE_COUNTER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "cc/debug/ring_buffer.h"
+#include "ui/gfx/frame_time.h"
 
 namespace cc {
 
 // This class maintains a history of timestamps, and provides functionality to
 // intelligently compute average frames per second.
 class FrameRateCounter {
  public:
   static scoped_ptr<FrameRateCounter> Create(bool has_impl_thread);
 
   int current_frame_number() const { return ring_buffer_.CurrentIndex(); }
   int dropped_frame_count() const { return dropped_frame_count_; }
   size_t time_stamp_history_size() const { return ring_buffer_.BufferSize(); }
 
-  void SaveTimeStamp(base::TimeTicks timestamp, bool software);
+  void SaveTimeStamp(gfx::FrameTime timestamp, bool software);
 
   // n = 0 returns the oldest frame interval retained in the history, while n =
   // time_stamp_history_size() - 1 returns the most recent frame interval.
   base::TimeDelta RecentFrameInterval(size_t n) const;
 
   // This is a heuristic that can be used to ignore frames in a reasonable way.
   // Returns true if the given frame interval is too fast or too slow, based on
   // constant thresholds.
   bool IsBadFrameInterval(
       base::TimeDelta interval_between_consecutive_frames) const;
 
   void GetMinAndMaxFPS(double* min_fps, double* max_fps) const;
   double GetAverageFPS() const;
 
-  typedef RingBuffer<base::TimeTicks, 136> RingBufferType;
+  typedef RingBuffer<gfx::FrameTime, 136> RingBufferType;
   RingBufferType::Iterator begin() const { return ring_buffer_.Begin(); }
   RingBufferType::Iterator end() const { return ring_buffer_.End(); }
 
  private:
   explicit FrameRateCounter(bool has_impl_thread);
 
   RingBufferType ring_buffer_;
 
   bool has_impl_thread_;
   int dropped_frame_count_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameRateCounter);
 };
 
 }  // namespace cc
 
 #endif  // CC_DEBUG_FRAME_RATE_COUNTER_H_