Update perf page_set to use story_set

tools/perf/page_sets/maps.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 page_sets import webgl_supported_shared_state
+from telemetry import story
 from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
-
-from page_sets import webgl_supported_shared_state
 
 
 class MapsPage(page_module.Page):
 
   def __init__(self, page_set):
     super(MapsPage, self).__init__(
       url='http://localhost:10020/tracker.html',
       page_set=page_set,
       name='Maps.maps_002',
       shared_page_state_class=(
           webgl_supported_shared_state.WebGLSupportedSharedState))
     self.archive_data_file = 'data/maps.json'
 
   def RunNavigateSteps(self, action_runner):
     super(MapsPage, self).RunNavigateSteps(action_runner)
     action_runner.Wait(3)
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateInteraction('MapAnimation'):
       action_runner.WaitForJavaScriptCondition('window.testDone', 120)
 
 
-class MapsPageSet(page_set_module.PageSet):
+class MapsPageSet(story.StorySet):
 
   """ Google Maps examples """
 
   def __init__(self):
     super(MapsPageSet, self).__init__(
         archive_data_file='data/maps.json',
-        bucket=page_set_module.PUBLIC_BUCKET)
+        cloud_storage_bucket=story.PUBLIC_BUCKET)
 
     self.AddUserStory(MapsPage(self))