Add live tests for measuring data savings metrics

tools/chrome_proxy/live_tests/pagesets/metrics.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 import story
 
 
-class CorsBypassPage(page_module.Page):
+class MetricsPage(page_module.Page):
 
   def __init__(self, url, page_set):
-    super(CorsBypassPage, self).__init__(url=url, page_set=page_set)
+    super(MetricsPage, self).__init__(url=url, page_set=page_set)
 
 
-class CorsBypassStorySet(story.StorySet):
+class MetricsStorySet(story.StorySet):
 
-  """ Chrome proxy test sites """
+  """ Chrome proxy test sites for measuring data savings """
 
   def __init__(self):
-    super(CorsBypassStorySet, self).__init__()
+    super(MetricsStorySet, self).__init__()
 
     urls_list = [
-      'http://www.gstatic.com/chrome/googlezip/cors/',
+      'http://check.googlezip.net/metrics/',
     ]
 
     for url in urls_list:
-      self.AddStory(CorsBypassPage(url, self))
+      self.AddStory(MetricsPage(url, self))