Update perf page_set to use story_set

tools/perf/page_sets/tough_ad_cases.py

 # Copyright 2015 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 import story
 from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
 
 
 class SwiffyPage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(SwiffyPage, self).__init__(url=url, page_set=page_set,
                                      make_javascript_deterministic=False)
 
   def RunNavigateSteps(self, action_runner):
     super(SwiffyPage, self).RunNavigateSteps(action_runner)
     # Swiffy overwrites toString() to return a constant string, so "undo" that
     # here so that we don't think it has stomped over console.time.
     action_runner.EvaluateJavaScript(
         'Function.prototype.toString = function() { return "[native code]"; }')
     # Make sure we have a reasonable viewport for mobile.
     viewport_js = (
         'var meta = document.createElement("meta");'
         'meta.name = "viewport";'
         'meta.content = "width=device-width";'
         'document.getElementsByTagName("head")[0].appendChild(meta);')
     action_runner.EvaluateJavaScript(viewport_js)
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateInteraction('ToughAd'):
       action_runner.Wait(10)
 
 
-class ToughAdCasesPageSet(page_set_module.PageSet):
+class ToughAdCasesPageSet(story.StorySet):
   """Pages for measuring performance with advertising content."""
 
   def __init__(self):
     super(ToughAdCasesPageSet, self).__init__(
         archive_data_file='data/tough_ad_cases.json',
-        bucket=page_set_module.INTERNAL_BUCKET)
+        cloud_storage_bucket=story.INTERNAL_BUCKET)
 
     base_url = 'http://localhost:8000'
 
     # See go/swiffy-chrome-samples for how to add new pages here or how to
     # update the existing ones.
     swiffy_pages = [
         'CICAgICQ15a9NxDIARjIASgBMghBC1XuTk8ezw.swiffy72.html',
         'shapes-CK7ptO3F8bi2KxDQAhiYAigBMgij6QBQtD2gyA.swiffy72.html',
         'CNP2xe_LmqPEKBCsAhj6ASgBMggnyMqth81h8Q.swiffy72.html',
         'clip-paths-CICAgMDO7Ye9-gEQ2AUYWigBMgjZxDii6aoK9w.swiffy72.html',
         'filters-CNLa0t2T47qJ_wEQoAEY2AQoATIIFaIdc7VMBr4.swiffy72.html',
         'shapes-CICAgMDO7cfIzwEQ1AMYPCgBMghqY8tqyRCArQ.swiffy72.html',
         'CICAgIDQ2Pb-MxCsAhj6ASgBMgi5DLoSO0gPbQ.swiffy72.html',
         'CICAgKCN39CopQEQoAEY2AQoATIID59gK5hjjIg.swiffy72.html',
         'CICAgKCNj4HgyAEQeBjYBCgBMgjQpPkOjyWNdw.1.swiffy72.html',
         'clip-paths-CILZhLqO_-27bxB4GNgEKAEyCC46kMLBXnMT.swiffy72.html',
         'CICAgMDOrcnRGRB4GNgEKAEyCP_ZBSfwUFsj.swiffy72.html',
     ]
     for page_name in swiffy_pages:
       url = base_url + '/' + page_name
       self.AddUserStory(SwiffyPage(url, self))