Add background stories to MobileSystemHealth

tools/perf/page_sets/system_health/system_health_stories.py

 # Copyright 2016 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 os
 
 from page_sets.system_health import platforms
 from page_sets.system_health import system_health_story
 
 from telemetry import story
 from telemetry.core import discover
 
 
 class SystemHealthStorySet(story.StorySet):
   """User stories for the System Health Plan.
 
   See https://goo.gl/Jek2NL.
   """
-  def __init__(self, platform, case=None, take_memory_measurement=False):
+  def __init__(self, platform, case=None, take_memory_measurement=False,
+               measure_in_background=False):
     super(SystemHealthStorySet, self).__init__(
         archive_data_file=('../data/system_health_%s.json' % platform),
         cloud_storage_bucket=story.PARTNER_BUCKET)
 
     assert platform in platforms.ALL_PLATFORMS
 
     for story_class in _IterAllSystemHealthStoryClasses():
       if (story_class.ABSTRACT_STORY or
           platform not in story_class.SUPPORTED_PLATFORMS or
           case and not story_class.NAME.startswith(case + ':')):
         continue
-      self.AddStory(story_class(self, take_memory_measurement))
+      self.AddStory(
+          story_class(self, take_memory_measurement, measure_in_background))
 
 
 class DesktopSystemHealthStorySet(SystemHealthStorySet):
   """Desktop user stories for the System Health Plan.
 
   Note: This story set is only intended to be used for recording stories via
   tools/perf/record_wpr. If you would like to use it in a benchmark, please use
   the generic SystemHealthStorySet class instead (you'll need to override the
   CreateStorySet method of your benchmark).
   """
@@ skipping 17 matching lines @@
 
 def _IterAllSystemHealthStoryClasses():
   start_dir = os.path.dirname(os.path.abspath(__file__))
   # Sort the classes by their names so that their order is stable and
   # deterministic.
   for unused_cls_name, cls in sorted(discover.DiscoverClasses(
       start_dir=start_dir,
       top_level_dir=os.path.dirname(start_dir),
       base_class=system_health_story.SystemHealthStory).iteritems()):
     yield cls