Task Execution Duration metrics added as a new benchmark

tools/perf/page_sets/key_mobile_sites.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 page_set as page_set_module
 
 
 class KeyMobileSitesPage(page_module.Page):
 
   def __init__(self, url, page_set, name=''):
     super(KeyMobileSitesPage, self).__init__(
         url=url, page_set=page_set, name=name,
-        credentials_path = 'data/credentials.json')
+        credentials_path='data/credentials.json')
     self.user_agent_type = 'mobile'
     self.archive_data_file = 'data/key_mobile_sites.json'
 
   def RunSmoothness(self, action_runner):
     interaction = action_runner.BeginGestureInteraction(
         'ScrollAction', is_smooth=True)
     action_runner.ScrollPage()
     interaction.End()
 
   def RunRepaint(self, action_runner):
     action_runner.RepaintContinuously(seconds=5)
 
+  def RunTaskExecutionTime(self, action_runner):
+    interaction = action_runner.BeginGestureInteraction(
+        'ScrollAction', is_smooth=True)
+    action_runner.ScrollPage()
+    interaction.End()
+
 
 class Page1(KeyMobileSitesPage):
 
   """ Why: Top news site """
 
   def __init__(self, page_set):
     super(Page1, self).__init__(
       url='http://nytimes.com/',
       page_set=page_set)
 
@@ skipping 502 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.AddPage(KeyMobileSitesPage(url, self))