Update perf page_set to use story_set

tools/perf/page_sets/polymer.py

Index: tools/perf/page_sets/polymer.py
diff --git a/tools/perf/page_sets/polymer.py b/tools/perf/page_sets/polymer.py
index e40aac775cbf32af2503e509ebef02d9399c5b35..b01ee00a5528cf71de61243e3327041b088507f4 100644
--- a/tools/perf/page_sets/polymer.py
+++ b/tools/perf/page_sets/polymer.py
@@ -1,8 +1,8 @@
 # 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 page_set as page_set_module
 from telemetry.page import shared_page_state
 
 
@@ -215,12 +215,12 @@ class PolymerSampler(PolymerPage):
                                  speed_in_pixels_per_second=300)
 
 
-class PolymerPageSet(page_set_module.PageSet):
+class PolymerPageSet(story.StorySet):
 
   def __init__(self, run_no_page_interactions=False):
     super(PolymerPageSet, self).__init__(
       archive_data_file='data/polymer.json',
-      bucket=page_set_module.PUBLIC_BUCKET)
+      cloud_storage_bucket=story.PUBLIC_BUCKET)
 
     self.AddUserStory(PolymerCalculatorPage(self, run_no_page_interactions))
     self.AddUserStory(PolymerShadowPage(self, run_no_page_interactions))