Update perf page_set to use story_set

tools/perf/page_sets/tough_canvas_cases.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.
+from telemetry import story
 from telemetry.page import page as page_module
-from telemetry.page import page_set as page_set_module
 
 
 class ToughCanvasCasesPage(page_module.Page):
 
   def __init__(self, url, page_set):
     super(ToughCanvasCasesPage, self).__init__(url=url, page_set=page_set)
     self.archive_data_file = 'data/tough_canvas_cases.json'
 
   def RunNavigateSteps(self, action_runner):
     super(ToughCanvasCasesPage, self).RunNavigateSteps(action_runner)
     action_runner.WaitForJavaScriptCondition(
         "document.readyState == 'complete'")
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateInteraction('CanvasAnimation'):
       action_runner.Wait(5)
 
 
 class MicrosofFirefliesPage(ToughCanvasCasesPage):
 
   def __init__(self, page_set):
     super(MicrosofFirefliesPage, self).__init__(
       # pylint: disable=C0301
       url='http://ie.microsoft.com/testdrive/Performance/Fireflies/Default.html',
       page_set=page_set)
 
 
-class ToughCanvasCasesPageSet(page_set_module.PageSet):
+class ToughCanvasCasesPageSet(story.StorySet):
 
   """
   Description: Self-driven Canvas2D animation examples
   """
 
   def __init__(self):
     super(ToughCanvasCasesPageSet, self).__init__(
       archive_data_file='data/tough_canvas_cases.json',
-      bucket=page_set_module.PARTNER_BUCKET)
+      cloud_storage_bucket=story.PARTNER_BUCKET)
 
     # Crashes on Galaxy Nexus. crbug.com/314131
     # self.AddUserStory(MicrosofFirefliesPage(self))
 
     # Failing on Nexus 5 (http://crbug.com/364248):
     # 'http://geoapis.appspot.com/agdnZW9hcGlzchMLEgtFeGFtcGxlQ29kZRjh1wIM',
 
     urls_list = [
       'http://mudcu.be/labs/JS1k/BreathingGalaxies.html',
       'http://runway.countlessprojects.com/prototype/performance_test.html',
@@ skipping 27 matching lines @@
       'file://tough_canvas_cases/canvas2d_balls_common/bouncing_balls.html?ball=filled_path&back=gradient',
       # pylint: disable=C0301
       'file://tough_canvas_cases/canvas2d_balls_common/bouncing_balls.html?ball=text&back=white&ball_count=15',
       'file://tough_canvas_cases/canvas-animation-no-clear.html',
       'file://../../../chrome/test/data/perf/canvas_bench/single_image.html',
       'file://../../../chrome/test/data/perf/canvas_bench/many_images.html'
     ]
 
     for url in urls_list:
       self.AddUserStory(ToughCanvasCasesPage(url, self))