Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/chromevox/injected/initial_speech.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 Defines the initial speech call.
  */
 
 goog.provide('cvox.InitialSpeech');
 
@@ skipping 31 matching lines @@
 
     // Allow the web author to disable reading the page title on load
     // by adding aria-hidden=true to the <title> element.
     var titleElement = document.querySelector('head > title');
     if (titleElement && titleElement.getAttribute('aria-hidden') == 'true') {
       title = null;
     }
 
     if (title && !disableSpeak) {
       cvox.ChromeVox.tts.speak(
-          title, cvox.AbstractTts.QUEUE_MODE_FLUSH);
+          title, cvox.QueueMode.FLUSH);
     }
     cvox.BrailleOverlayWidget.getInstance().init();
   }
 
   // Initialize live regions and speak alerts.
   cvox.LiveRegions.init(
-      new Date(), cvox.AbstractTts.QUEUE_MODE_QUEUE, disableSpeak);
+      new Date(), cvox.QueueMode.QUEUE, disableSpeak);
 
   // If our activeElement is on body, try to sync to the first element. This
   // actually happens inside of NavigationManager.reset, which doesn't get
   // called until AbstractHost.onPageLoad, but we need to speak and braille the
   // initial node here.
   if (document.hasFocus() && document.activeElement == document.body) {
     cvox.ChromeVox.navigationManager.syncToBeginning();
   }
 
   // If we had a previous position recorded, update to it.
   if (cvox.ChromeVox.position[document.location.href]) {
     var pos = cvox.ChromeVox.position[document.location.href];
     cvox.ChromeVox.navigationManager.updateSelToArbitraryNode(
         document.elementFromPoint(pos.x, pos.y));
   }
 
   // If this iframe has focus, speak and braille the current focused element.
   if (document.hasFocus()) {
     if (!disableSpeak) {
       cvox.ChromeVoxEventSuspender.withSuspendedEvents(function() {
         cvox.ChromeVox.navigationManager.finishNavCommand(
-            '', true, cvox.AbstractTts.QUEUE_MODE_QUEUE);
+            '', true, cvox.QueueMode.QUEUE);
       })();
     }
   }
 };