Update telemetry benchmark to stress-test WebRTC.

tools/perf/page_sets/webrtc_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.
 import os
 
 from telemetry import story
 from telemetry.page import page as page_module
 
 
 WEBRTC_TEST_PAGES_URL = 'https://test.webrtc.org/manual/'
@@ skipping 150 matching lines @@
     super(Page9, self).__init__(
         url= WEBRTC_TEST_PAGES_URL + 'multiple-peerconnections/',
         name='multiple_peerconnections',
         page_set=page_set)
 
   def RunPageInteractions(self, action_runner):
     with action_runner.CreateInteraction('Action_Create_PeerConnection',
                                          repeatable=False):
       # Set the number of peer connections to create to 15.
       action_runner.ExecuteJavaScript(
-          'document.getElementById("peer-connections-input").value=15')
-      action_runner.ClickElement('button[id="start-test-button"]')
+          'document.getElementById("num-peerconnections").value=15')
+      action_runner.ExecuteJavaScript(
+          'document.getElementById("cpuoveruse-detection").checked=false')
+      action_runner.ClickElement('button[id="start-test"]')
       action_runner.Wait(45)
 
 
 class WebrtcGetusermediaPageSet(story.StorySet):
   """WebRTC tests for local getUserMedia: video capture and playback."""
 
   def __init__(self):
     super(WebrtcGetusermediaPageSet, self).__init__(
         archive_data_file='data/webrtc_getusermedia_cases.json',
         cloud_storage_bucket=story.PUBLIC_BUCKET)
@@ skipping 51 matching lines @@
 class WebrtcRenderingPageSet(story.StorySet):
   """WebRTC tests for video rendering."""
 
   def __init__(self):
     super(WebrtcRenderingPageSet, self).__init__(
         archive_data_file='data/webrtc_smoothness_cases.json',
         cloud_storage_bucket=story.PARTNER_BUCKET)
 
     self.AddStory(Page2(self))
     self.AddStory(Page8(self))