Add average commit time to perf tests.

tools/gpu/gpu_tools/texture_upload_benchmark.py

Index: tools/gpu/gpu_tools/texture_upload_benchmark.py
diff --git a/tools/gpu/gpu_tools/texture_upload_benchmark.py b/tools/gpu/gpu_tools/texture_upload_benchmark.py
index 3f42459ef73953d9393de7cccf907e9d20fd1b24..1fcdcce600dec92dd5c09d8bfbe8023f9d9c38cb 100644
--- a/tools/gpu/gpu_tools/texture_upload_benchmark.py
+++ b/tools/gpu/gpu_tools/texture_upload_benchmark.py
@@ -7,8 +7,18 @@ 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():