cc: Improve frame/commit accounting

cc/CCFrameRateCounter.cpp

 // 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.
 
 #include "config.h"
 
 #if USE(ACCELERATED_COMPOSITING)
 #include "CCFrameRateCounter.h"
 
 #include "CCProxy.h"
 #include <public/Platform.h>
 #include <wtf/CurrentTime.h>
 
 namespace cc {
 
 const double CCFrameRateCounter::kFrameTooFast = 1.0 / 70.0; // measured in seconds
 const double CCFrameRateCounter::kFrameTooSlow = 1.0 / 12.0;
-const double CCFrameRateCounter::kDroppedFrameTime = 1.0 / 50.0;
 
 // safeMod works on -1, returning m-1 in that case.
 static inline int safeMod(int number, int modulus)
 {
     return (number + modulus) % modulus;
 }
 
 inline double CCFrameRateCounter::frameInterval(int frameNumber) const
 {
     return m_timeStampHistory[frameIndex(frameNumber)] -
         m_timeStampHistory[frameIndex(frameNumber - 1)];
 }
 
 inline int CCFrameRateCounter::frameIndex(int frameNumber) const
 {
     return safeMod(frameNumber, kTimeStampHistorySize);
 }
 
 CCFrameRateCounter::CCFrameRateCounter()
     : m_currentFrameNumber(1)
-    , m_droppedFrameCount(0)
 {
     m_timeStampHistory[0] = currentTime();
     m_timeStampHistory[1] = m_timeStampHistory[0];
     for (int i = 2; i < kTimeStampHistorySize; i++)
         m_timeStampHistory[i] = 0;
 }
 
 void CCFrameRateCounter::markBeginningOfFrame(double timestamp)
 {
     m_timeStampHistory[frameIndex(m_currentFrameNumber)] = timestamp;
     double frameIntervalSeconds = frameInterval(m_currentFrameNumber);
 
     if (CCProxy::hasImplThread() && m_currentFrameNumber > 0) {
         double drawDelayMs = frameIntervalSeconds * 1000.0;
         WebKit::Platform::current()->histogramCustomCounts("Renderer4.CompositorThreadImplDrawDelay", static_cast<int>(drawDelayMs), 1, 120, 60);
     }
-
-    if (!isBadFrameInterval(frameIntervalSeconds) && frameIntervalSeconds > kDroppedFrameTime)
-        ++m_droppedFrameCount;
 }
 
 void CCFrameRateCounter::markEndOfFrame()
 {
     m_currentFrameNumber += 1;
 }
 
 bool CCFrameRateCounter::isBadFrameInterval(double intervalBetweenConsecutiveFrames) const
 {
     bool schedulerAllowsDoubleFrames = !CCProxy::hasImplThread();
@@ skipping 52 matching lines @@
 double CCFrameRateCounter::timeStampOfRecentFrame(int n)
 {
     ASSERT(n >= 0 && n < kTimeStampHistorySize);
     int desiredIndex = (frameIndex(m_currentFrameNumber) + n) % kTimeStampHistorySize;
     return m_timeStampHistory[desiredIndex];
 }
 
 } // namespace cc
 
 #endif // USE(ACCELERATED_COMPOSITING)