Updating references from story.display_name to story.name

tools/perf/page_sets/story_set_unittest.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.
 
 import os
 
 import page_sets
 
 from telemetry import decorators
 from telemetry import page
@@ skipping 19 matching lines @@
                                                       self.top_level_dir):
       if story_set_class is page_sets.ToughSchedulingCasesPageSet:
         continue
       story_set = story_set_class()
       for story in story_set:
         if isinstance(story, page.Page):
           self.assertFalse(
             story.synthetic_delays,
             'Page %s in page set %s has non empty synthetic delay. '
             'Synthetic delay is no longer supported. See crbug.com/508538.' %
-            (story.display_name, story_set.Name()))
+            (story.name, story_set.Name()))
 
   def testNoStorySetDefinedWithUnnamedStories(self):
     for story_set_class in self.GetAllStorySetClasses(self.story_sets_dir,
                                                       self.top_level_dir):
       story_set = story_set_class()
       for story in story_set:
         self.assertTrue(story.name != '',
                         'stories must be named: ' + str(story_set_class))