Update perf page_set to use story_set

tools/perf/page_sets/inbox.py

 # 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 import story
+from telemetry.page import page as page_module
 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
 
 _SCROLL_LIST_ITEM = ('.scroll-list-item .%s')
 _NUM_REPEATS_FOR_EMAIL_OPEN = 40
 _OPEN_CLOSE_WAIT_TIME = 0.3
 
 
 class InboxPage(page_module.Page):
   """A class defining inbox page for telemetry."""
 
   def __init__(self, page_set):
@@ skipping 49 matching lines @@
     action_runner.Wait(_OPEN_CLOSE_WAIT_TIME)
 
   def OpenCloseConv(self, action_runner):
     # Wait for the page to load and start background sync
     self._WaitForInitialSync(action_runner)
     for _ in range(0, _NUM_REPEATS_FOR_EMAIL_OPEN):
       self._OpenAndCloseEmail(action_runner)
     action_runner.Wait(10)
 
 
-class InboxPageSet(page_set_module.PageSet):
+class InboxPageSet(story.StorySet):
 
   """Inbox page set."""
 
   def __init__(self):
     super(InboxPageSet, self).__init__(
         archive_data_file='data/inbox_data.json',
-        bucket=page_set_module.INTERNAL_BUCKET
+        cloud_storage_bucket=story.INTERNAL_BUCKET
         )
 
     self.AddUserStory(InboxPage(self))