Update perf page_set to use story_set

tools/perf/page_sets/simple_mobile_sites_fling.py

Index: tools/perf/page_sets/simple_mobile_sites_fling.py
diff --git a/tools/perf/page_sets/simple_mobile_sites_fling.py b/tools/perf/page_sets/simple_mobile_sites_fling.py
index 69a91c24d6ac23e387b40ae3719bd3d40717454a..1497d3df3a59ba88e43fedd95a5d0345f89bb728 100644
--- a/tools/perf/page_sets/simple_mobile_sites_fling.py
+++ b/tools/perf/page_sets/simple_mobile_sites_fling.py
@@ -2,9 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 from page_sets import fling_gesture_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
 
 
 class SimpleFlingPage(page_module.Page):
@@ -31,14 +30,14 @@ class SimpleFlingPage(page_module.Page):
                               distance='500',
                               speed_in_pixels_per_second=5000)
 
-class SimpleMobileSitesFlingPageSet(page_set_module.PageSet):
+class SimpleMobileSitesFlingPageSet(story.StorySet):
 
   """ Simple mobile sites """
 
   def __init__(self):
     super(SimpleMobileSitesFlingPageSet, self).__init__(
       archive_data_file='data/simple_mobile_sites.json',
-      bucket=page_set_module.PUBLIC_BUCKET)
+      cloud_storage_bucket=story.PUBLIC_BUCKET)
 
     fling_page_list = [
       # Why: Scrolls moderately complex pages (up to 60 layers)
@@ -51,4 +50,3 @@ class SimpleMobileSitesFlingPageSet(page_set_module.PageSet):
 
     for url in fling_page_list:
       self.AddUserStory(SimpleFlingPage(url, self))
-