Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js

Index: chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js
diff --git a/chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js b/chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js
index c8b85c0745e2982cbd3cb0d9f3351dcb0b602459..ba4444e21725f3d3a5052bd8038d7487c28c3f04 100644
--- a/chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js
+++ b/chrome/browser/resources/chromeos/chromevox/walkers/table_walker.js
@@ -18,6 +18,7 @@ goog.require('cvox.BrailleUtil');
 goog.require('cvox.DescriptionUtil');
 goog.require('cvox.DomUtil');
 goog.require('cvox.NavDescription');
+goog.require('cvox.QueueMode');
 goog.require('cvox.TraverseTable');
 
 /**
@@ -204,7 +205,7 @@ cvox.TableWalker.prototype.nextCol = function(sel) {
  */
 cvox.TableWalker.prototype.announceHeaders = function(sel) {
   cvox.ChromeVox.tts.speak(this.getHeaderText_(sel),
-                           cvox.AbstractTts.QUEUE_MODE_FLUSH,
+                           cvox.QueueMode.FLUSH,
                            cvox.AbstractTts.PERSONALITY_ANNOTATION);
   return sel;
 };
@@ -217,7 +218,7 @@ cvox.TableWalker.prototype.announceHeaders = function(sel) {
 cvox.TableWalker.prototype.speakTableLocation = function(sel) {
   cvox.ChromeVox.navigationManager.speakDescriptionArray(
       this.getLocationDescription_(sel),
-      cvox.AbstractTts.QUEUE_MODE_FLUSH,
+      cvox.QueueMode.FLUSH,
       null);
   return sel;
 };