Revert of Disable mossiella.com in tough_layout_cases.

tools/perf/page_sets/tough_layout_cases.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 cache_temperature as cache_temperature_module
 from telemetry.page import page as page_module
 from telemetry.page import shared_page_state
 from telemetry import story
 
 
 class ToughLayoutCasesPage(page_module.Page):
@@ skipping 16 matching lines @@
     super(ToughLayoutCasesPageSet, self).__init__(
       archive_data_file='data/tough_layout_cases.json',
       cloud_storage_bucket=story.PARTNER_BUCKET)
     if cache_temperatures is None:
       cache_temperatures = [cache_temperature_module.ANY]
 
     urls_list = [
       'http://oilevent.com',
       'http://www.muzoboss.ru',
       'http://natunkantha.com',
-      # http://crbug.com/671645
-      #'http://www.mossiella.com',
+      'http://www.mossiella.com',
       'http://bookish.com',
       'http://mydiyclub.com',
       'http://amarchoti.blogspot.com',
       'http://picarisimo.es',
       'http://chinaapache.com',
       'http://indoritel.com'
     ]
 
     for url in urls_list:
       for temp in cache_temperatures:
         self.AddStory(ToughLayoutCasesPage(url, self, cache_temperature=temp))