Add telemetry to track the time an event spent waiting for the main thread.

tools/perf/metrics/smoothness.py

 # Copyright 2013 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 telemetry.core import util
 
 class SmoothnessMetrics(object):
   def __init__(self, tab):
     self._tab = tab
@@ skipping 137 matching lines @@
               Average(s.touch_ui_latency, s.touch_ui_count, 1000, 3),
               data_type='unimportant')
   results.Add('average_touch_acked_latency', 'ms',
               Average(s.touch_acked_latency, s.touch_acked_count,
                       1000, 3),
               data_type='unimportant')
   results.Add('average_scroll_update_latency', 'ms',
               Average(s.scroll_update_latency, s.scroll_update_count,
                       1000, 3),
               data_type='unimportant')
+  results.Add('average_impl_to_main_touch_event_latency', 'ms',
+              Average(s.total_impl_to_main_touch_event_latency,
+                      s.impl_to_main_touch_event_count, 1000, 3),
+              data_type='unimportant')
+  results.Add('average_impl_to_main_gesture_scroll_event_latency', 'ms',
+              Average(s.total_impl_to_main_gesture_scroll_event_latency,
+                      s.impl_to_main_gesture_scroll_event_count, 1000, 3),
+              data_type='unimportant')