cc: Improve frame/commit accounting

cc/CCFrameRateCounter.cpp

Index: cc/CCFrameRateCounter.cpp
diff --git a/cc/CCFrameRateCounter.cpp b/cc/CCFrameRateCounter.cpp
index 521b50166b59d75370c12d96b217c53af22f7271..affbb93ffe8da00fd364047ddf126cce9f975380 100644
--- a/cc/CCFrameRateCounter.cpp
+++ b/cc/CCFrameRateCounter.cpp
@@ -15,7 +15,6 @@ 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)
@@ -36,7 +35,6 @@ inline int CCFrameRateCounter::frameIndex(int frameNumber) const
 
 CCFrameRateCounter::CCFrameRateCounter()
     : m_currentFrameNumber(1)
-    , m_droppedFrameCount(0)
 {
     m_timeStampHistory[0] = currentTime();
     m_timeStampHistory[1] = m_timeStampHistory[0];
@@ -53,9 +51,6 @@ void CCFrameRateCounter::markBeginningOfFrame(double timestamp)
         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()