Update perf page_set to use story_set

tools/perf/page_sets/key_mobile_sites.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 page_sets import key_mobile_sites_pages
+from telemetry import story
+from telemetry.page import page as page_module
 from telemetry.page import shared_page_state
-from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
-
-from page_sets import key_mobile_sites_pages
 
 
 class KeyMobileSitesPage(page_module.Page):
 
   def __init__(self, url, page_set, name='', labels=None,
                action_on_load_complete=False):
     super(KeyMobileSitesPage, self).__init__(
         url=url, page_set=page_set, name=name,
         shared_page_state_class=shared_page_state.SharedMobilePageState,
         credentials_path='data/credentials.json', labels=labels)
     self.archive_data_file = 'data/key_mobile_sites.json'
     self.action_on_load_complete = action_on_load_complete
 
 
-class KeyMobileSitesPageSet(page_set_module.PageSet):
+class KeyMobileSitesPageSet(story.StorySet):
 
   """ Key mobile sites with smooth interactions. """
 
   def __init__(self):
     super(KeyMobileSitesPageSet, self).__init__(
       archive_data_file='data/key_mobile_sites.json',
-      bucket=page_set_module.PARTNER_BUCKET)
+      cloud_storage_bucket=story.PARTNER_BUCKET)
 
 
     # Add pages with predefined classes that contain custom navigation logic.
     predefined_page_classes = [
       key_mobile_sites_pages.CapitolVolkswagenPage,
       key_mobile_sites_pages.TheVergeArticlePage,
       key_mobile_sites_pages.CnnArticlePage,
       key_mobile_sites_pages.FacebookPage,
       key_mobile_sites_pages.YoutubeMobilePage,
       key_mobile_sites_pages.LinkedInPage,
@@ skipping 129 matching lines @@
       ('http://www.baidu.com/s?wd=barack+obama&rsv_bp=0&rsv_spt=3&rsv_sug3=9&'
        'rsv_sug=0&rsv_sug4=3824&rsv_sug1=3&inputT=4920'),
       # Why: Top search engine
       'http://www.bing.com/search?q=sloths',
       # Why: Good example of poor initial scrolling
       'http://ftw.usatoday.com/2014/05/spelling-bee-rules-shenanigans'
     ]
 
     for url in urls_list:
       self.AddUserStory(KeyMobileSitesPage(url, self))