Add cleanup for measurements that use tracing

tools/perf/metrics/timeline.py

 # Copyright 2014 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 collections
 import itertools
 
 from metrics import Metric
 from telemetry.core.timeline.model import TimelineModel
 from telemetry.core.timeline import bounds
 from telemetry.page import page_measurement
@@ skipping 43 matching lines @@
   def Stop(self, page, tab):
     timeline_data = tab.browser.StopTracing()
     self._model = TimelineModel(timeline_data)
     self._renderer_process = self._model.GetRendererProcessFromTab(tab)
     self._action_ranges = [ action.GetActiveRangeOnTimeline(self._model)
                             for action in self._actions ]
     # Make sure no action ranges overlap
     for combo in itertools.combinations(self._action_ranges, 2):
       assert not combo[0].Intersects(combo[1])
 
+  def CleanUp(self, tab):
+    if tab.browser.is_tracing_running:
+      tab.browser.StopTracing()
+
   def AddActionToIncludeInMetric(self, action):
     self._actions.append(action)
 
   @property
   def model(self):
     return self._model
 
   @model.setter
   def model(self, model):
     self._model = model
@@ skipping 251 matching lines @@
     num_frames = self.CountSlices(frame_slices, FrameTraceName)
 
     # Report the desired results and details.
     for thread_results in thread_category_results.values():
       if thread_results.name in self.results_to_report:
         thread_results.AddResults(num_frames, results)
       # TOOD(nduca): When generic results objects are done, this special case
       # can be replaced with a generic UI feature.
       if thread_results.name in self.details_to_report:
         thread_results.AddDetailedResults(num_frames, results)