Telemetry: smoothness measurement throws MissingTimelineMarker.

tools/perf/measurements/smoothness.py

 # Copyright (c) 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.
 from metrics import loading
 from metrics import smoothness
 from metrics.gpu_rendering_stats import GpuRenderingStats
 from telemetry.page import page_measurement
 
+
 class DidNotScrollException(page_measurement.MeasurementFailure):
   def __init__(self):
     super(DidNotScrollException, self).__init__('Page did not scroll')
 
+
 class MissingDisplayFrameRate(page_measurement.MeasurementFailure):
   def __init__(self, name):
     super(MissingDisplayFrameRate, self).__init__(
         'Missing display frame rate metrics: ' + name)
 
+
+class MissingTimelineMarker(page_measurement.MeasurementFailure):
+  def __init__(self):
+    super(MissingTimelineMarker, self).__init__('Timeline marker not found')
+
+
 class Smoothness(page_measurement.PageMeasurement):
   def __init__(self):
     super(Smoothness, self).__init__('smoothness')
     self.force_enable_threaded_compositing = False
     self._metrics = None
 
   def AddCommandLineOptions(self, parser):
     parser.add_option('--report-all-results', dest='report_all_results',
                       action='store_true',
                       help='Reports all data collected, not just FPS')
@@ skipping 22 matching lines @@
     if not action.CanBeBound():
       self._metrics.Stop()
     tab.browser.StopTracing()
 
   def FindTimelineMarker(self, timeline):
     events = [s for
               s in timeline.GetAllEventsOfName(
                   smoothness.TIMELINE_MARKER)
               if s.parent_slice == None]
     if len(events) != 1:
-      raise LookupError, 'timeline marker not found'
+      raise MissingTimelineMarker()
     return events[0]
 
   def MeasurePage(self, page, tab, results):
     rendering_stats_deltas = self._metrics.deltas
 
     if not (rendering_stats_deltas['numFramesSentToScreen'] > 0):
       raise DidNotScrollException()
 
     loading.LoadingMetric().AddResults(tab, results)
 
     smoothness.CalcFirstPaintTimeResults(results, tab)
 
     timeline = tab.browser.GetTraceResultAndReset().AsTimelineModel()
     timeline_marker = self.FindTimelineMarker(timeline)
     benchmark_stats = GpuRenderingStats(timeline_marker,
                                         rendering_stats_deltas,
                                         self._metrics.is_using_gpu_benchmarking)
     smoothness.CalcResults(benchmark_stats, results)
 
     if self.options.report_all_results:
       for k, v in rendering_stats_deltas.iteritems():
         results.Add(k, '', v)
 
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       for r in tab.browser.platform.GetRawDisplayFrameRateMeasurements():
         if r.value is None:
           raise MissingDisplayFrameRate(r.name)
         results.Add(r.name, r.unit, r.value)