Update perf page_set to use story_set

tools/perf/page_sets/key_mobile_sites.py

Index: tools/perf/page_sets/key_mobile_sites.py
diff --git a/tools/perf/page_sets/key_mobile_sites.py b/tools/perf/page_sets/key_mobile_sites.py
index 833714e4028c43f1287a74def88a5f2212c941e3..9b4677e3be53a1f9bc1109e933f81d4442ca9d86 100644
--- a/tools/perf/page_sets/key_mobile_sites.py
+++ b/tools/perf/page_sets/key_mobile_sites.py
@@ -1,11 +1,10 @@
 # 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.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
+from telemetry import story
+from telemetry.page import page as page_module
+from telemetry.page import shared_page_state
 
 
 class KeyMobileSitesPage(page_module.Page):
@@ -20,14 +19,14 @@ class KeyMobileSitesPage(page_module.Page):
     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.