cc: Fixed computation of dropped frames.

cc/debug/frame_rate_counter.cc

 // 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 "cc/debug/frame_rate_counter.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/metrics/histogram.h"
@@ skipping 55 matching lines @@
       UMA_HISTOGRAM_CUSTOM_COUNTS("Renderer4.CompositorThreadImplDrawDelay",
                                   frame_interval_seconds.InMilliseconds(),
                                   1,
                                   120,
                                   60);
     }
   }
 
   if (!IsBadFrameInterval(frame_interval_seconds) &&
       frame_interval_seconds.InSecondsF() > kDroppedFrameTime)
-    ++dropped_frame_count_;
+    dropped_frame_count_ +=
+        frame_interval_seconds.InSecondsF() / kDroppedFrameTime;
 }
 
 bool FrameRateCounter::IsBadFrameInterval(
     base::TimeDelta interval_between_consecutive_frames) const {
   double delta = interval_between_consecutive_frames.InSecondsF();
   bool scheduler_allows_double_frames = !has_impl_thread_;
   bool interval_too_fast =
       scheduler_allows_double_frames ? delta < kFrameTooFast : delta <= 0.0;
   bool interval_too_slow = delta > kFrameTooSlow;
   return interval_too_fast || interval_too_slow;
@@ skipping 51 matching lines @@
 
   if (frame_count) {
     DCHECK_GT(frame_times_total, 0.0);
     average_fps = frame_count / frame_times_total;
   }
 
   return average_fps;
 }
 
 }  // namespace cc