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

tools/perf/metrics/smoothness_unittest.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 unittest
 
 from metrics import smoothness
 from metrics.gpu_rendering_stats import GpuRenderingStats
 from telemetry.page import page
 from telemetry.page.page_measurement_results import PageMeasurementResults
 
@@ skipping 19 matching lines @@
         'totalTilesAnalyzed': 160,
         'totalTileAnalysisTimeInSeconds': 1.6,
         'solidColorTilesAnalyzed': 40,
         'inputEventCount': 170,
         'totalInputLatency': 1.7,
         'touchUICount': 180,
         'totalTouchUILatency': 1.8,
         'touchAckedCount': 190,
         'totalTouchAckedLatency': 1.9,
         'scrollUpdateCount': 200,
-        'totalScrollUpdateLatency': 2.0}
+        'totalScrollUpdateLatency': 2.0,
+        'implToMainTouchEventCount': 100,
+        'totalImplToMainTouchEventLatency': 0.7,
+        'implToMainGestureScrollEventCount': 133,
+        'totalImplToMainGestureScrollEventLatency': 2.7}
     stats = GpuRenderingStats(mock_rendering_stats_deltas)
 
     res = PageMeasurementResults()
     res.WillMeasurePage(page.Page('http://foo.com/', None))
     smoothness.CalcResults(stats, res)
     res.DidMeasurePage()
 
     # Scroll Results
     self.assertAlmostEquals(
         1.0 / 100.0 * 1000.0,
@@ skipping 53 matching lines @@
         res.page_results[0]['average_latency'].value)
     self.assertAlmostEquals(
         1.8 / 180.0 * 1000.0,
         res.page_results[0]['average_touch_ui_latency'].value)
     self.assertAlmostEquals(
         1.9 / 190.0 * 1000.0,
         res.page_results[0]['average_touch_acked_latency'].value)
     self.assertAlmostEquals(
         2.0 / 200.0 * 1000.0,
         res.page_results[0]['average_scroll_update_latency'].value)