Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/cvox2/background/background.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.
 
 /**
  * @fileoverview The entry point for all ChromeVox2 related code for the
  * background page.
  */
 
 goog.provide('cvox2.Background');
@@ skipping 75 matching lines @@
                           this.onAutomationEvent.bind(this),
                           true);
   },
 
   /**
    * A generic handler for all desktop automation events.
    * @param {AutomationEvent} evt The event.
    */
   onAutomationEvent: function(evt) {
     var output = evt.target.attributes.name + ' ' + evt.target.role;
-    cvox.ChromeVox.tts.speak(output, cvox.AbstractTts.QUEUE_MODE_FLUSH);
+    cvox.ChromeVox.tts.speak(output, cvox.QueueMode.FLUSH);
     cvox.ChromeVox.braille.write(cvox.NavBraille.fromText(output));
     chrome.accessibilityPrivate.setFocusRing([evt.target.location]);
   },
 
   /**
    * Handles chrome.commands.onCommand.
    * @param {string} command
    */
   onGotCommand: function(command) {
   },
@@ skipping 16 matching lines @@
   disableClassicChromeVox_: function(tabId) {
     chrome.tabs.executeScript(
           tabId,
           {'code': 'try { window.disableChromeVox(); } catch(e) { }\n',
            'allFrames': true});
   }
 };
 
 /** @type {cvox2.Background} */
 cvox2.global.backgroundObj = new cvox2.Background();