Make sure that tracing is always cleaned up for v8_gc_times page_test

tools/perf/measurements/v8_gc_times_unittest.py

 # Copyright 2015 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 telemetry.core import wpr_modes
 from telemetry.page import page as page_module
 from telemetry.results import page_test_results
 from telemetry.timeline import model as model_module
 from telemetry.unittest_util import options_for_unittests
 from telemetry.unittest_util import page_test_test_case
@@ skipping 220 matching lines @@
 
     self._AssertResultsEqual(expected, _ActualValues(results))
 
   def _AssertResultsEqual(self, expected, actual):
     for key in expected.iterkeys():
       self.assertIn(key, actual.keys())
       self.assertEqual(expected[key], actual[key],
           'Result for [' + key + '] - expected ' + str(expected[key]) +
           ' but got ' + str(actual[key]))
 
+  def testCleanUpTrace(self):
+    self.TestTracingCleanedUp(v8_gc_times.V8GCTimes, self._options)
+
 
 def _ActualValues(results):
   return dict(list(
       (v.name, (v.units, v.value))
       for v in results.all_page_specific_values
       ))
 
 
 def _GetEmptyResults():
   return {'cpu_time': ('ms', 0.0),
           'duration': ('ms', 0.0),
           'v8_gc_incremental_marking': ('ms', 0.0),
           'v8_gc_incremental_marking_idle_deadline_overrun': ('ms', 0.0),
           'v8_gc_incremental_marking_outside_idle': ('ms', 0.0),
           'v8_gc_incremental_marking_percentage_idle': ('idle%', 0.0),
           'v8_gc_mark_compactor': ('ms', 0.0),
           'v8_gc_mark_compactor_idle_deadline_overrun': ('ms', 0.0),
           'v8_gc_mark_compactor_outside_idle': ('ms', 0.0),
           'v8_gc_mark_compactor_percentage_idle': ('idle%', 0.0),
           'v8_gc_scavenger': ('ms', 0.0),
           'v8_gc_scavenger_idle_deadline_overrun': ('ms', 0.0),
           'v8_gc_scavenger_outside_idle': ('ms', 0.0),
           'v8_gc_scavenger_percentage_idle': ('idle%', 0.0),
           'v8_gc_total': ('ms', 0.0),
           'v8_gc_total_idle_deadline_overrun': ('ms', 0.0),
           'v8_gc_total_outside_idle': ('ms', 0.0)}