Use an enum for ChromeVox queue mode.

chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js

Index: chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js
diff --git a/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js b/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js
index 034be6a39ef6f2d3ed5dbf46c0557f47b0e03667..8da75b3651402fa89a9267ac03e330947e0cb37a 100644
--- a/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js
+++ b/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_deprecated.js
@@ -59,7 +59,7 @@ cvox.LiveRegionsDeprecated.INITIAL_SILENCE_MS = 2000;
  */
 cvox.LiveRegionsDeprecated.init = function(pageLoadTime, queueMode, disableSpeak) {
   if (queueMode == undefined) {
-    queueMode = cvox.AbstractTts.QUEUE_MODE_FLUSH;
+    queueMode = cvox.QueueMode.FLUSH;
   }
 
   cvox.LiveRegionsDeprecated.pageLoadTime = pageLoadTime;
@@ -70,7 +70,7 @@ cvox.LiveRegionsDeprecated.init = function(pageLoadTime, queueMode, disableSpeak
     if (cvox.LiveRegionsDeprecated.updateLiveRegion(regions[i], queueMode,
                                           disableSpeak)) {
       anyRegionsAnnounced = true;
-      queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
+      queueMode = cvox.QueueMode.QUEUE;
     }
   }
 
@@ -188,11 +188,11 @@ cvox.LiveRegionsDeprecated.updateLiveRegion = function(region, queueMode, disabl
   // Announce the changes with the appropriate politeness level.
   var live = cvox.AriaUtil.getAriaLive(region);
   if (live == 'polite') {
-    queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
+    queueMode = cvox.QueueMode.QUEUE;
   }
   for (i = 0; i < messages.length; i++) {
     messages[i].speak(queueMode);
-    queueMode = cvox.AbstractTts.QUEUE_MODE_QUEUE;
+    queueMode = cvox.QueueMode.QUEUE;
   }
 
   return true;