cc: switch FPS counter graph back to a frame based X axis

cc/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_FRAME_RATE_COUNTER_H_
 #define CC_FRAME_RATE_COUNTER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
@@ skipping 34 matching lines @@
     // - 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 = 170;
+    static const int kTimeStampHistorySize = 130;
 
     bool m_hasImplThread;
 
     int m_currentFrameNumber;
     base::TimeTicks m_timeStampHistory[kTimeStampHistorySize];
 
     int m_droppedFrameCount;
 
     DISALLOW_COPY_AND_ASSIGN(FrameRateCounter);
 };
 
 }  // namespace cc
 
 #endif  // CC_FRAME_RATE_COUNTER_H_