cc: Improve frame/commit accounting

cc/CCFrameRateCounter.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 CCFrameRateCounter_h
 #define CCFrameRateCounter_h
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "base/basictypes.h"
 #include <wtf/PassOwnPtr.h>
 
 namespace cc {
 
 // This class maintains a history of timestamps, and provides functionality to
 // intelligently compute average frames per second (and standard deviation).
 class CCFrameRateCounter {
 public:
     static PassOwnPtr<CCFrameRateCounter> create()
     {
         return adoptPtr(new CCFrameRateCounter());
     }
 
     void markBeginningOfFrame(double timestamp);
     void markEndOfFrame();
-    int currentFrameNumber() const { return m_currentFrameNumber; }
+    uint64_t currentFrameNumber() const { return m_currentFrameNumber; }
     void getAverageFPSAndStandardDeviation(double& averageFPS, double& standardDeviation) const;
     int timeStampHistorySize() const { return kTimeStampHistorySize; }
 
     // n = 0 returns the oldest frame retained in the history,
     // while n = timeStampHistorySize() - 1 returns the timestamp most recent frame.
     double timeStampOfRecentFrame(int /* n */);
 
     // 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(double intervalBetweenConsecutiveFrames) const;
 
-    int droppedFrameCount() const { return m_droppedFrameCount; }
-
 private:
     CCFrameRateCounter();
 
     double frameInterval(int frameNumber) const;
     int frameIndex(int frameNumber) const;
     bool isBadFrame(int frameNumber) const;
 
     // Two thresholds (measured in seconds) that describe what is considered to be a "no-op frame" that should not be counted.
     // - if the frame is too fast, then given our compositor implementation, the frame probably was a no-op and did not draw.
     // - if the frame is too slow, then there is probably not animating content, so we should not pollute the average.
     static const double kFrameTooFast;
     static const double kFrameTooSlow;
 
     // If a frame takes longer than this threshold (measured in seconds) then we
     // (naively) assume that it missed a screen refresh; that is, we dropped a frame.
     // FIXME: Determine this threshold based on monitor refresh rate, crbug.com/138642.
     static const double kDroppedFrameTime;
 
     static const int kTimeStampHistorySize = 120;
 
-    int m_currentFrameNumber;
+    uint64_t m_currentFrameNumber;
     double m_timeStampHistory[kTimeStampHistorySize];
 
-    int m_droppedFrameCount;
-
     DISALLOW_COPY_AND_ASSIGN(CCFrameRateCounter);
 };
 
 } // namespace cc
 
 #endif // USE(ACCELERATED_COMPOSITING)
 
 #endif