Fix page interaction with CnnArticlePage

tools/perf/page_sets/key_mobile_sites_smooth.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.page import page as page_module
 from telemetry.page import shared_page_state
 from telemetry import story
 
 from page_sets import key_mobile_sites_pages
 
 
@@ skipping 107 matching lines @@
 
 class AmazonNicolasCageSmoothPage(
   key_mobile_sites_pages.AmazonNicolasCagePage):
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateGestureInteraction('ScrollAction'):
       action_runner.ScrollElement(
           selector='#search',
           distance_expr='document.body.scrollHeight - window.innerHeight')
 
+class CNNArticleSmoothPage(
+      key_mobile_sites_pages.CnnArticlePage):
+
+  def RunPageInteractions(self, action_runner):
+    with action_runner.CreateGestureInteraction('ScrollAction'):
+      # With default top_start_ratio=0.5 the corresponding element in this page
+      # will not be in the root scroller.
+      action_runner.ScrollPage(top_start_ratio=0.01)
 
 class KeyMobileSitesSmoothPageSet(story.StorySet):
 
   """ Key mobile sites with smooth interactions. """
 
   def __init__(self):
     super(KeyMobileSitesSmoothPageSet, self).__init__(
       archive_data_file='data/key_mobile_sites_smooth.json',
       cloud_storage_bucket=story.PARTNER_BUCKET)
 
 
     # Add pages with predefined classes that contain custom navigation logic.
     predefined_page_classes = [
       key_mobile_sites_pages.CapitolVolkswagenPage,
       key_mobile_sites_pages.TheVergeArticlePage,
-      key_mobile_sites_pages.CnnArticlePage,
       key_mobile_sites_pages.FacebookPage,
       key_mobile_sites_pages.YoutubeMobilePage,
       key_mobile_sites_pages.YahooAnswersPage,
       key_mobile_sites_pages.GoogleNewsMobilePage,
     ]
     for page_class in predefined_page_classes:
       self.AddStory(
         _CreatePageClassWithSmoothInteractions(page_class)(self))
 
     self.AddStory(
       _CreatePageClassWithSmoothInteractions(LinkedInSmoothPage)(self))
     self.AddStory(WowwikiSmoothPage(self))
 
     # Add pages with custom page interaction logic.
 
     # Page behaves non-deterministically, replaced with test version for now.
     # self.AddStory(GroupClonedSmoothPage(self))
     # mean_input_event_latency cannot be tracked correctly for
     # GroupClonedListImagesPage.
     # See crbug.com/409086.
     # self.AddStory(GroupClonedListImagesSmoothPage(self))
     self.AddStory(GoogleNewsMobile2SmoothPage(self))
     self.AddStory(AmazonNicolasCageSmoothPage(self))
+    self.AddStory(CNNArticleSmoothPage(self))
 
     # Add pages with custom labels.
 
     # Why: Top news site.
     self.AddStory(KeyMobileSitesSmoothPage(
       url='http://nytimes.com/', page_set=self, labels=['fastpath']))
 
     # Why: Image-heavy site.
     self.AddStory(KeyMobileSitesSmoothPage(
       url='http://cuteoverload.com', page_set=self, labels=['fastpath']))
@@ skipping 96 matching lines @@
       ('http://www.baidu.com/s?wd=barack+obama&rsv_bp=0&rsv_spt=3&rsv_sug3=9&'
        'rsv_sug=0&rsv_sug4=3824&rsv_sug1=3&inputT=4920'),
       # Why: Top search engine
       'http://www.bing.com/search?q=sloths',
       # Why: Good example of poor initial scrolling
       'http://ftw.usatoday.com/2014/05/spelling-bee-rules-shenanigans'
     ]
 
     for url in urls_list:
       self.AddStory(KeyMobileSitesSmoothPage(url, self))