Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/common/nav_description.js

Index: chrome/browser/resources/chromeos/chromevox/common/nav_description.js
diff --git a/chrome/browser/resources/chromeos/chromevox/common/nav_description.js b/chrome/browser/resources/chromeos/chromevox/common/nav_description.js
index 3dea53a488a8b23b6087c80d73701aa3f8b95147..1f98de8fce7d0ac76b8f3a1a2fef7f90aa1c4a5c 100644
--- a/chrome/browser/resources/chromeos/chromevox/common/nav_description.js
+++ b/chrome/browser/resources/chromeos/chromevox/common/nav_description.js
@@ -90,8 +90,7 @@ cvox.NavDescription.prototype.pushEarcon = function(earconId) {
 
 /**
  * Speak this nav description with the given queue mode.
- * @param {number=} queueMode The queue mode: cvox.AbstractTts.QUEUE_MODE_FLUSH
- *     for flush, cvox.AbstractTts.QUEUE_MODE_QUEUE for adding to queue.
+ * @param {cvox.QueueMode=} queueMode The queue mode.
  * @param {function()=} startCallback Function called when this starts speaking.
  * @param {function()=} endCallback Function called when this ends speaking.

[Peter Lundblad, 2014/09/29 13:51:04]

nit: optional parameters should have opt_ prepended to their names.

[dmazzoni, 2014/09/30 22:01:20]

Done.

  */
@@ -113,13 +112,13 @@ cvox.NavDescription.prototype.speak = function(
   var speakArgs = new Array();
   if (this.context) {
     speakArgs.push([this.context, queueMode, makeAnnotationProps()]);
-    queueMode = 1;
+    queueMode = cvox.QueueMode.QUEUE;
   }
 
   speakArgs.push([this.text,
                   queueMode,
                   this.personality ? this.personality : {}]);
-  queueMode = 1;
+  queueMode = cvox.QueueMode.QUEUE;
 
   if (this.userValue) {
     speakArgs.push([this.userValue, queueMode, {}]);