Use page_set_module.PageSet instead of story.StorySet

tools/skp/page_sets/skia_css3gradients_desktop.py

 # 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.
 # pylint: disable=W0401,W0614
 
 
-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 SkiaBuildbotDesktopPage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(SkiaBuildbotDesktopPage, self).__init__(
         url=url,
         page_set=page_set,
         credentials_path='data/credentials.json',
         shared_page_state_class=shared_page_state.SharedDesktopPageState)
     self.archive_data_file = 'data/skia_css3gradients_desktop.json'
 
   def RunSmoothness(self, action_runner):
     action_runner.ScrollElement()
 
   def RunNavigateSteps(self, action_runner):
     action_runner.Navigate(self.url)
     action_runner.Wait(15)
 
 
-class SkiaCss3gradientsDesktopPageSet(story.StorySet):
+class SkiaCss3gradientsDesktopPageSet(page_set_module.PageSet):
 
   """ Pages designed to represent the median, not highly optimized web """
 
   def __init__(self):
     super(SkiaCss3gradientsDesktopPageSet, self).__init__(
       archive_data_file='data/skia_css3gradients_desktop.json')
 
     urls_list = [
       # Why: http://code.google.com/p/chromium/issues/detail?id=168448
       'https://www.webkit.org/blog/1424/css3-gradients/',
     ]
 
     for url in urls_list:
       self.AddUserStory(SkiaBuildbotDesktopPage(url, self))