Update perf page_set to use story_set

tools/perf/page_sets/key_search_mobile.py

 # Copyright 2014 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 shared_page_state
-from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
 
 
 class KeySearchMobilePage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(KeySearchMobilePage, self).__init__(
         url=url, page_set=page_set, credentials_path = 'data/credentials.json',
         shared_page_state_class=shared_page_state.SharedMobilePageState)
     self.archive_data_file = 'data/key_search_mobile.json'
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateGestureInteraction('ScrollAction'):
       action_runner.ScrollPage()
 
 
-class KeySearchMobilePageSet(page_set_module.PageSet):
+class KeySearchMobilePageSet(story.StorySet):
 
   """ Key mobile search queries on google """
 
   def __init__(self):
     super(KeySearchMobilePageSet, self).__init__(
       archive_data_file='data/key_search_mobile.json',
-      bucket=page_set_module.PUBLIC_BUCKET)
+      cloud_storage_bucket=story.PUBLIC_BUCKET)
 
     urls_list = [
       # Why: An empty page should be as snappy as possible
       'http://www.google.com/',
       # Why: A reasonable search term with no images or ads usually
       'https://www.google.com/search?q=science',
       # Why: A reasonable search term with images but no ads usually
       'http://www.google.com/search?q=orange',
       # Why: An address search
       # pylint: disable=C0301
@@ skipping 17 matching lines @@
       # Why: Definitions
       'http://www.google.com/search?q=define+define',
       # Why: Local results
       'https://www.google.com/search?q=burritos+94110',
       # Why: Graph
       'http://www.google.com/search?q=x^3'
     ]
 
     for url in urls_list:
       self.AddUserStory(KeySearchMobilePage(url, self))