Let tests request a browser restart for each page in the pageset.

This reduces the noise on painting measurements from 30% to 5%. I will revisit
why when I can, but I thought I'd throw this out as a temporary solution to getting good stable numbers is key for us.

R=tonyg
NOTRY=True

Review URL: https://chromiumcodereview.appspot.com/11888020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@177018 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 21 insertions, 3 deletions

diff --git a/tools/telemetry/telemetry/multi_page_benchmark.py b/tools/telemetry/telemetry/multi_page_benchmark.py
index 9261b83..c24def3 100644
--- a/tools/telemetry/telemetry/multi_page_benchmark.py
+++ b/tools/telemetry/telemetry/multi_page_benchmark.py
@@ -39,8 +39,13 @@ class MultiPageBenchmark(page_test.PageTest):
               'document.querySelector('%s').children.length')
            results.Add('children', 'count', child_count)
   """
-  def __init__(self, interaction_name=''):
-    super(MultiPageBenchmark, self).__init__('_RunTest', interaction_name)
+  def __init__(self,
+               interaction_name_to_run='',
+               needs_browser_restart_after_each_run=False):
+    super(MultiPageBenchmark, self).__init__(
+      '_RunTest',
+      interaction_name_to_run,
+      needs_browser_restart_after_each_run)
 
   def _RunTest(self, page, tab, results):
     results.WillMeasurePage(page)
diff --git a/tools/telemetry/telemetry/page_runner.py b/tools/telemetry/telemetry/page_runner.py
index e386877..3cfb6d4 100644
--- a/tools/telemetry/telemetry/page_runner.py
+++ b/tools/telemetry/telemetry/page_runner.py
@@ -162,6 +162,10 @@ class PageRunner(object):
 
             if options.trace_dir:
               self._EndTracing(state, options, page)
+
+            if test.needs_browser_restart_after_each_run:
+              state.Close()
+
             break
           except browser_gone_exception.BrowserGoneException:
             logging.warning('Lost connection to browser. Retrying.')
diff --git a/tools/telemetry/telemetry/page_test.py b/tools/telemetry/telemetry/page_test.py
index 702c22d..8fbd2d0 100644
--- a/tools/telemetry/telemetry/page_test.py
+++ b/tools/telemetry/telemetry/page_test.py
@@ -30,7 +30,10 @@ class PageTestResults(object):
 class PageTest(object):
   """A class styled on unittest.TestCase for creating page-specific tests."""
 
-  def __init__(self, test_method_name, interaction_name_to_run=''):
+  def __init__(self,
+               test_method_name,
+               interaction_name_to_run='',
+               needs_browser_restart_after_each_run=False):
     self.options = None
     try:
       self._test_method = getattr(self, test_method_name)
@@ -38,6 +41,12 @@ class PageTest(object):
       raise ValueError, 'No such method %s.%s' % (
         self.__class_, test_method_name) # pylint: disable=E1101
     self._interaction_name_to_run = interaction_name_to_run
+    self._needs_browser_restart_after_each_run = (
+        needs_browser_restart_after_each_run)
+
+  @property
+  def needs_browser_restart_after_each_run(self):
+    return self._needs_browser_restart_after_each_run
 
   def AddCommandLineOptions(self, parser):
     """Override to expose command-line options for this benchmark.