Made WebRTC AQ test two-way, adjusted volume on Mac.

chrome/test/data/webrtc/peerconnection.js

 /**
  * 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.
  */
 
 /**
  * We need a STUN server for some API calls.
  * @private
  */
@@ skipping 191 matching lines @@
     peerConnection_().addIceCandidate(new RTCIceCandidate(iceCandidate,
         function() { success_('addIceCandidate'); },
         function(error) { failure_('addIceCandidate', error); }
     ));
   });
 
   returnToTest('ok-received-candidates');
 }
 
 /**
+ * Sets the mute state of the selected media element.
+ *
+ * Returns ok-muted on success.
+ *
+ * @param elementId The id of the element to mute.
+ * @param muted The mute state to set.
+ */
+function setMediaElementMuted(elementId, muted) {
+  var element = document.getElementById(elementId);
+  if (!element)
+    throw failTest('Cannot mute ' + elementId + '; does not exist.');
+  element.muted = muted;
+  returnToTest('ok-muted');
+}
+
+/**
  * Returns
  */
 function hasSeenCryptoInSdp() {
   returnToTest(gHasSeenCryptoInSdp);
 }
 
 // Internals.
 
 /** @private */
 function createPeerConnection_(stun_server) {
@@ skipping 86 matching lines @@
 function parseJson_(json) {
   // Escape since the \r\n in the SDP tend to get unescaped.
   jsonWithEscapedLineBreaks = json.replace(/\r\n/g, '\\r\\n');
   try {
     return JSON.parse(jsonWithEscapedLineBreaks);
   } catch (exception) {
     failTest('Failed to parse JSON: ' + jsonWithEscapedLineBreaks + ', got ' +
              exception);
   }
 }