[system health] Add media browsing stories.

tools/perf/page_sets/system_health/loading_stories.py

 # Copyright 2016 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 page_sets.system_health import platforms
 from page_sets.system_health import system_health_story
 
 from page_sets.login_helpers import dropbox_login
 from page_sets.login_helpers import google_login
 
@@ skipping 179 matching lines @@
     if has_button:
       action_runner.ClickElement(selector=self._CLOSE_BUTTON_SELECTOR)
 
 
 class LoadWikipediaStory(_LoadingStory):
   NAME = 'load:news:wikipedia'
   URL = 'https://en.wikipedia.org/wiki/Science'
 
 
 ################################################################################
-# Audio and video.
+# Audio, images, and video.
 ################################################################################
 
 
 class LoadYouTubeStory(_LoadingStory):
   # No way to disable autoplay on desktop.
   NAME = 'load:media:youtube'
   URL = 'https://www.youtube.com/watch?v=QGfhS1hfTWw&autoplay=false'
 
 
 class LoadDailymotionStory(_LoadingStory):
@@ skipping 26 matching lines @@
   URL = 'https://www.flickr.com/photos/tags/farm'
 
   def _DidLoadDocument(self, action_runner):
     # Wait until the 'Recently tagged' view loads.
     action_runner.WaitForJavaScriptCondition('''
         document.querySelector(
             '.search-photos-everyone-trending-view .photo-list-view')
                 !== null''')
 
 
+class LoadImgur(_LoadingStory):
+  NAME = 'load:media:imgur'
+  URL = 'http://imgur.com/gallery/5UlBN'
+
+
 ################################################################################
 # Online tools (documents, emails, storage, ...).
 ################################################################################
 
 
 class LoadDocsStory(_LoadingStory):
   NAME = 'load:tools:docs'
   URL = (
       'https://docs.google.com/document/d/1GvzDP-tTLmJ0myRhUAfTYWs3ZUFilUICg8psNHyccwQ/edit?usp=sharing')
 
@@ skipping 113 matching lines @@
   URL = 'http://www.miniclip.com/games/en/'
   # Desktop only (requires Flash).
   SUPPORTED_PLATFORMS = platforms.DESKTOP_ONLY
 
 
 class LoadAlphabettyStory(_LoadingStory):
   NAME = 'load:games:alphabetty'
   URL = 'https://king.com/play/alphabetty'
   # Desktop only (requires Flash).
   SUPPORTED_PLATFORMS = platforms.DESKTOP_ONLY