Stop browse:social:twitter scrolling wrong element

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
 
 
 class _BrowsingStory(system_health_story.SystemHealthStory):
   """Abstract base class for browsing stories.
 
   A browsing story visits items on the main page. Subclasses provide
   CSS selector to identify the items and implement interaction using
   the helper methods of this class.
   """
 
   IS_SINGLE_PAGE_APP = False
   ITEM_SELECTOR = NotImplemented
+  # Defaults to using the body element if not set.
+  CONTAINER_SELECTOR = None
   ABSTRACT_STORY = True
 
   def _WaitForNavigation(self, action_runner):
     if not self.IS_SINGLE_PAGE_APP:
       action_runner.WaitForNavigate()
 
   def _NavigateToItem(self, action_runner, index):
     item_selector = 'document.querySelectorAll("%s")[%d]' % (
         self.ITEM_SELECTOR, index)
     # Only scrolls if element is not currently in viewport.
     action_runner.WaitForElement(element_function=item_selector)
-    action_runner.ScrollPageToElement(element_function=item_selector)
+    action_runner.ScrollPageToElement(
+        element_function=item_selector,
+        container_selector=self.CONTAINER_SELECTOR)
     self._ClickLink(action_runner, item_selector)
 
   def _ClickLink(self, action_runner, element_function):
     action_runner.WaitForElement(element_function=element_function)
     action_runner.ClickElement(element_function=element_function)
     self._WaitForNavigation(action_runner)
 
   def _NavigateBack(self, action_runner):
     action_runner.NavigateBack()
     self._WaitForNavigation(action_runner)
@@ skipping 142 matching lines @@
   URL = 'https://www.reddit.com/r/news/top/?sort=top&t=week'
   IS_SINGLE_PAGE_APP = True
   ITEM_SELECTOR = '.PostHeader__post-title-line'
   SUPPORTED_PLATFORMS = platforms.MOBILE_ONLY
 
 
 class TwitterMobileStory(_NewsBrowsingStory):
   NAME = 'browse:social:twitter'
   URL = 'https://www.twitter.com/nasa'
   ITEM_SELECTOR = '.Tweet-text'
+  CONTAINER_SELECTOR = '.NavigationSheet'
   SUPPORTED_PLATFORMS = platforms.MOBILE_ONLY
 
 
 @decorators.Disabled('win',  # crbug.com/662971
                      'mac')  # crbug.com/663025
 class TwitterDesktopStory(_NewsBrowsingStory):
   NAME = 'browse:social:twitter'
   URL = 'https://www.twitter.com/nasa'
   IS_SINGLE_PAGE_APP = True
   ITEM_SELECTOR = '.tweet-text'
@@ skipping 217 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.