[BattOr] Add mac BattOr test for steady state cases.

tools/perf/page_sets/idle_after_loading_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.
 from telemetry.page import page as page_module
 from telemetry import story
 
 
+# TODO(rnephew): Move to seperate file and merge with mac_gpu_sites BasePage.
+class _BasePage(page_module.Page):
+  def __init__(self, page_set, url, wait_in_seconds):
+    super(_BasePage, self).__init__(url=url, page_set=page_set)
+    self._wait_in_seconds = wait_in_seconds
+
+  def RunPageInteractions(self, action_runner):
+    action_runner.Wait(self._wait_in_seconds)
+
+
 class IdleAfterLoadingStories(story.StorySet):
   """Historically, Chrome has high CPU usage on these sites after the page has
   loaded. These user stories let Chrome idle on the page."""
 
-  def __init__(self):
+  def __init__(self, wait_in_seconds=0):
     super(IdleAfterLoadingStories, self).__init__(
         archive_data_file='data/idle_after_loading_stories.json',
         cloud_storage_bucket=story.PARTNER_BUCKET)
 
     # Chrome has high idle CPU usage on this site, even after its quiesced.
     # https://crbug.com/638365.
-    self.AddStory(page_module.Page(
+    urls = [
         'http://www.labradortraininghq.com/labrador-training/how-to-crate-train'
-        '-a-puppy/#How_Long_DoesIt_Take_To_Crate_Train_A_Puppy', page_set=self))
+        '-a-puppy/#How_Long_DoesIt_Take_To_Crate_Train_A_Puppy'
+    ]
+    for url in urls:
+      self.AddStory(_BasePage(self, url, wait_in_seconds))