cc: Improve frame/commit accounting

tools/perf/perf_tools/scrolling_benchmark.py

 # Copyright (c) 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.
 import os
 
 from chrome_remote_control import multi_page_benchmark
 from chrome_remote_control import util
 
 class DidNotScrollException(multi_page_benchmark.MeasurementFailure):
   def __init__(self):
     super(DidNotScrollException, self).__init__('Page did not scroll')
 
 def CalcScrollResults(rendering_stats_deltas, results):
-  num_frames_sent_to_screen = rendering_stats_deltas['numFramesSentToScreen']
+  num_frames_sent_to_screen = rendering_stats_deltas['rendererFrameCount']
 
   mean_frame_time_seconds = (
     rendering_stats_deltas['totalTimeInSeconds'] /
       float(num_frames_sent_to_screen))
 
   dropped_percent = (
     rendering_stats_deltas['droppedFrameCount'] /
-    float(num_frames_sent_to_screen))
+    float(rendering_stats_deltas['vsyncCount']))
 
   results.Add('mean_frame_time', 'ms', round(mean_frame_time_seconds * 1000, 3))
   results.Add('dropped_percent', '%', round(dropped_percent * 100, 1))
 
 class ScrollingBenchmark(multi_page_benchmark.MultiPageBenchmark):
   def __init__(self):
     super(ScrollingBenchmark, self).__init__()
 
   def AddOptions(self, parser):
     parser.add_option('--no-gpu-benchmarking-extension', action='store_true',
@@ skipping 29 matching lines @@
       tab.runtime.Execute('(function() { var element = document.body; %s})();' %
                           start_scroll_js)
 
     # Poll for scroll benchmark completion.
     util.WaitFor(lambda: tab.runtime.Evaluate(
         'window.__renderingStatsDeltas'), 60)
 
     rendering_stats_deltas = tab.runtime.Evaluate(
       'window.__renderingStatsDeltas')
 
-    if not (rendering_stats_deltas['numFramesSentToScreen'] > 0):
+    if not (rendering_stats_deltas['rendererFrameCount'] > 0):
       raise DidNotScrollException()
     return rendering_stats_deltas
 
   def CustomizeBrowserOptions(self, options):
     if not options.no_gpu_benchmarking_extension:
       options.extra_browser_args.append('--enable-gpu-benchmarking')
 
   def MeasurePage(self, page, tab, results):
     rendering_stats_deltas = self.ScrollPageFully(page, tab)
     CalcScrollResults(rendering_stats_deltas, results)
     if self.options.report_all_results:
       for k, v in rendering_stats_deltas.iteritems():
         results.Add(k, '', v)