service_worker.service_worker perf test: call StopTracing() to cleanup

tools/perf/benchmarks/service_worker.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 page_sets
 import re
 
 from core import perf_benchmark
 
@@ skipping 77 matching lines @@
 
 class _ServiceWorkerMeasurement(page_test.PageTest):
   """Measure Speed Index and TRACE_EVENTs"""
 
   def __init__(self):
     super(_ServiceWorkerMeasurement, self).__init__()
     self._timeline_controller = timeline_controller.TimelineController()
     self._speed_index = speedindex.SpeedIndexMetric()
     self._page_open_times = collections.defaultdict(int)
 
+  def DidRunPage(self, platform):
+    if platform.tracing_controller.is_tracing_running:
+      platform.tracing_controller.StopTracing()
+
   def WillNavigateToPage(self, page, tab):
     self._timeline_controller.SetUp(page, tab)
     self._timeline_controller.Start(tab)
     self._speed_index.Start(page, tab)
 
   def ValidateAndMeasurePage(self, page, tab, results):
     runner = action_runner.ActionRunner(tab)
     # timeline_controller requires creation of at least a single interaction
     # record. service_worker should be refactored to follow the
     # timeline_based_measurement or it should not re-use timeline_controller
@@ skipping 68 matching lines @@
   The page set is a benchmark page that generates many concurrent requests
   handled by a service worker that does respondWith(new Response()). The test
   result is the response times.
   """
   test = _ServiceWorkerMicroBenchmarkMeasurement
   page_set = page_sets.ServiceWorkerMicroBenchmarkPageSet
 
   @classmethod
   def Name(cls):
     return 'service_worker.service_worker_micro_benchmark'