[System Health] Reenable tests failing due to bug in ScrollToElement

tools/perf/page_sets/system_health/browsing_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 pinterest_login
 
 from telemetry import decorators
@@ skipping 78 matching lines @@
 # crash with OOM.
 @decorators.Disabled('android')
 class CnnStory(_NewsBrowsingStory):
   """The second top website in http://www.alexa.com/topsites/category/News"""
   NAME = 'browse:news:cnn'
   URL = 'http://edition.cnn.com/'
   ITEM_SELECTOR = '.cd__content > h3 > a'
   ITEMS_TO_VISIT = 2
 
 
-@decorators.Disabled('android')  # crbug.com/664518
 class FacebookMobileStory(_NewsBrowsingStory):
   NAME = 'browse:social:facebook'
   URL = 'https://www.facebook.com/rihanna'
   ITEM_SELECTOR = 'article ._5msj'
   # We scroll further than usual so that Facebook fetches enough items
   # (crbug.com/631022)
   MAIN_PAGE_SCROLL_REPEAT = 1
   SUPPORTED_PLATFORMS = platforms.MOBILE_ONLY
 
 
@@ skipping 141 matching lines @@
       if self.INCREMENT_INDEX_AFTER_EACH_ITEM:
         index += 1
 
 
   def _ViewMediaItem(self, action_runner, index):
     del index  # Unused.
     action_runner.tab.WaitForDocumentReadyStateToBeComplete()
     action_runner.Wait(self.ITEM_VIEW_TIME_IN_SECONDS)
 
 
-@decorators.Disabled('android')  # crbug.com/664518
 class ImgurMobileStory(_MediaBrowsingStory):
   NAME = 'browse:media:imgur'
   URL = 'http://imgur.com/gallery/5UlBN'
   ITEM_SELECTOR = '.Navbar-customAction'
   SUPPORTED_PLATFORMS = platforms.MOBILE_ONLY
   IS_SINGLE_PAGE_APP = True
 
 
 class ImgurDesktopStory(_MediaBrowsingStory):
   NAME = 'browse:media:imgur'
@@ skipping 90 matching lines @@
       inner_save_function = 'document.querySelector(".nameAndIcons")'
       action_runner.WaitForElement(element_function=inner_save_function)
       action_runner.ClickElement(element_function=inner_save_function)
       action_runner.Wait(1)  # Wait to make navigation realistic.
 
     # Close selection.
     x_element_function = ('document.querySelector('
                           '".Button.borderless.close.visible")')
     action_runner.ClickElement(element_function=x_element_function)
     action_runner.Wait(1)  # Wait to make navigation realistic.