Update perf page_set to use story_set

tools/perf/page_sets/mobile_memory.py

Index: tools/perf/page_sets/mobile_memory.py
diff --git a/tools/perf/page_sets/mobile_memory.py b/tools/perf/page_sets/mobile_memory.py
index f23a4f5a0271eca3aa549afba9e3eeb5ba8af64c..ddeeda983fec911b4cde51317b023ff23ec66aae 100644
--- a/tools/perf/page_sets/mobile_memory.py
+++ b/tools/perf/page_sets/mobile_memory.py
@@ -1,9 +1,9 @@
 # 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.page import shared_page_state
+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
 
 
 class MobileMemoryPage(page_module.Page):
@@ -73,14 +73,14 @@ class ScrollPage(MobileMemoryPage):
       action_runner.ScrollPage()
 
 
-class MobileMemoryPageSet(page_set_module.PageSet):
+class MobileMemoryPageSet(story.StorySet):
 
   """ Mobile sites with interesting memory characteristics """
 
   def __init__(self):
     super(MobileMemoryPageSet, self).__init__(
         archive_data_file='data/mobile_memory.json',
-        bucket=page_set_module.PARTNER_BUCKET)
+        cloud_storage_bucket=story.PARTNER_BUCKET)
 
     self.AddUserStory(GmailPage(self))
     self.AddUserStory(GoogleSearchPage(self))