Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/chromevox/background/options.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 ChromeVox options page.
  *
  */
 
 goog.provide('cvox.OptionsPage');
@@ skipping 168 matching lines @@
 
     // TODO(dtseng): Only basic conflict detection; it does not speak the
     // conflicting command. Nor does it detect prefix conflicts like Cvox+L vs
     // Cvox+L>L.
     if (cvox.OptionsPage.prefs.setKey(document.activeElement.id,
         this.keySequence)) {
       document.activeElement.value = keySeqStr;
     } else {
       announce = cvox.ChromeVox.msgs.getMsg('key_conflict', [announce]);
     }
-    cvox.OptionsPage.speak(announce);
+    cvox.OptionsPage.speak(announce, cvox.QueueMode.QUEUE);
     this.prevTime = currentTime;
 
     evt.preventDefault();
     evt.stopPropagation();
   }, cvox.OptionsPage), true);
 
   var categories = cvox.CommandStore.categories();
   for (var i = 0; i < categories.length; i++) {
     // Braille bindings can't be customized, so don't include them.
     if (categories[i] == 'braille') {
@@ skipping 82 matching lines @@
         this.modifierSeq_ = new cvox.KeySequence(evt, false);
       } else {
         this.modifierSeq_.addKeyEvent(evt);
       }
 
       //  Never allow non-modified keys.
       if (!this.modifierSeq_.isAnyModifierActive()) {
         // Indicate error and instructions excluding tab.
         if (evt.keyCode != 9) {
           cvox.OptionsPage.speak(
-              cvox.ChromeVox.msgs.getMsg('modifier_entry_error'), 0, {});
+              cvox.ChromeVox.msgs.getMsg('modifier_entry_error'),
+              cvox.QueueMode.FLUSH, {});
         }
         this.modifierSeq_ = null;
       } else {
         this.modifierCount_++;
       }
 
       // Don't trap tab or shift.
       if (!evt.shiftKey && evt.keyCode != 9) {
         evt.preventDefault();
         evt.stopPropagation();
       }
     }, true);
 
     cvoxKey.addEventListener('keyup', function(evt) {
       if (this.modifierSeq_) {
         this.modifierCount_--;
 
         if (this.modifierCount_ == 0) {
           var modifierStr =
               cvox.KeyUtil.keySequenceToString(this.modifierSeq_, true, true);
           evt.target.value = modifierStr;
           cvox.OptionsPage.speak(
-              cvox.ChromeVox.msgs.getMsg('modifier_entry_set', [modifierStr]));
+              cvox.ChromeVox.msgs.getMsg('modifier_entry_set', [modifierStr]),
+              cvox.QueueMode.QUEUE);
           localStorage['cvoxKey'] = modifierStr;
           this.modifierSeq_ = null;
         }
         evt.preventDefault();
         evt.stopPropagation();
       }
     }, true);
   }
 };
 
@@ skipping 222 matching lines @@
       el.style.display = 'none';
     }
   }
 };
 
 
 /**
  * Calls a {@code cvox.TtsInterface.speak} method in the background page to
  * speak an utterance.  See that method for further details.
  * @param {string} textString The string of text to be spoken.
- * @param {number=} queueMode The queue mode to use.
+ * @param {cvox.QueueMode} queueMode The queue mode to use.
  * @param {Object=} properties Speech properties to use for this utterance.
  */
 cvox.OptionsPage.speak = function(textString, queueMode, properties) {
   var speak =
       /** @type Function} */ (chrome.extension.getBackgroundPage()['speak']);
   speak.apply(null, arguments);
 };
 
 document.addEventListener('DOMContentLoaded', function() {
   cvox.OptionsPage.init();
 }, false);