Add average commit time to perf tests.

tools/gpu/gpu_tools/texture_upload_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.
 from chrome_remote_control import multi_page_benchmark
 from gpu_tools import scrolling_benchmark
 
 class TextureUploadBenchmark(scrolling_benchmark.ScrollingBenchmark):
   def MeasurePage(self, _, tab):
     rendering_stats_deltas = self.ScrollPageFully(tab)
+
+    if (("totalCommitCount" not in rendering_stats_deltas)
+        or rendering_stats_deltas["totalCommitCount"] == 0) :
+      averageCommitTimeMs = 0
+    else :
+      averageCommitTimeMs = (
+          1000 * rendering_stats_deltas["totalCommitTimeInSeconds"] /
+          rendering_stats_deltas["totalCommitCount"])
+
     return {
-      'texture_upload_count': rendering_stats_deltas['textureUploadCount']
+      'texture_upload_count': rendering_stats_deltas['textureUploadCount'],
+      'average_commit_time_ms': averageCommitTimeMs
     }
 
 def Main():
   return multi_page_benchmark.Main(TextureUploadBenchmark())