Trigger clean-up GCs between tests of Speedometer

tools/perf/benchmarks/speedometer.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.
 
 """Apple's Speedometer performance benchmark.
 
 Speedometer measures simulated user interactions in web applications.
 
 The current benchmark uses TodoMVC to simulate user actions for adding,
 completing, and removing to-do items. Speedometer repeats the same actions using
@@ skipping 24 matching lines @@
     'AngularJS-TodoMVC',
     'React-TodoMVC',
     'FlightJS-TodoMVC'
   ]
 
   def __init__(self):
     super(SpeedometerMeasurement, self).__init__()
 
   def CustomizeBrowserOptions(self, options):
     keychain_metric.KeychainMetric.CustomizeBrowserOptions(options)
+    options.AppendExtraBrowserArgs(['--js-flags=--expose_gc'])
 
   def ValidateAndMeasurePage(self, page, tab, results):
     tab.WaitForDocumentReadyStateToBeComplete()
     iterationCount = 10
     # A single iteration on android takes ~75 seconds, the benchmark times out
     # when running for 10 iterations.
     if tab.browser.platform.GetOSName() == 'android':
       iterationCount = 3
 
     tab.ExecuteJavaScript("""
         // Store all the results in the benchmarkClient
         benchmarkClient._measuredValues = []
         benchmarkClient.didRunSuites = function(measuredValues) {
           benchmarkClient._measuredValues.push(measuredValues);
           benchmarkClient._timeValues.push(measuredValues.total);
         };
+        benchmarkClient.willRunTest = function(suite, test) {
+          for (var i = 0; i < 5; i++) {
+            gc();
+          }
+        };
         benchmarkClient.iterationCount = %d;
         startTest();
         """ % iterationCount)
     tab.WaitForJavaScriptExpression(
         'benchmarkClient._finishedTestCount == benchmarkClient.testsCount', 600)
     results.AddValue(list_of_scalar_values.ListOfScalarValues(
         page, 'Total', 'ms',
         tab.EvaluateJavaScript('benchmarkClient._timeValues'), important=True))
 
     # Extract the timings for each suite
@@ skipping 19 matching lines @@
 
   def CreatePageSet(self, options):
     ps = page_set.PageSet(
         file_path=os.path.abspath(__file__),
         archive_data_file='../page_sets/data/speedometer.json',
         bucket=page_set.PUBLIC_BUCKET)
     ps.AddUserStory(page_module.Page(
         'http://browserbench.org/Speedometer/', ps, ps.base_dir,
         make_javascript_deterministic=False))
     return ps