Entering / exiting dialog notification should not interrupt live region.

chrome/browser/resources/chromeos/chromevox/host/interface/tts_interface.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 a Tts interface.
  *
  * All TTS engines in ChromeVox conform to the this interface.
  *
  */
 
+goog.provide('cvox.TtsCapturingEventListener');
+goog.provide('cvox.TtsCategory');
 goog.provide('cvox.TtsInterface');
-goog.provide('cvox.TtsCapturingEventListener');
+
+/**
+ * Categories for a speech utterance. This can be used with the
+ * CATEGORY_FLUSH queue mode, which flushes all utterances from a given
+ * category but not other utterances.
+ *
+ * NAV: speech related to explicit navigation, or focus changing.
+ *
+ * @enum {string}
+ */
+cvox.TtsCategory = {
+  LIVE: 'live',
+  NAV: 'nav'
+};
 
 /**
  * @interface
  * An interface for clients who want to get notified when an utterance
  * starts or ends from any source.
  */
 cvox.TtsCapturingEventListener = function() { };
 
 /**
  * Called when any utterance starts.
@@ skipping 50 matching lines @@
 cvox.TtsInterface.prototype.increaseOrDecreaseProperty =
     function(propertyName, increase) { };
 
 
 /**
  * Returns the default properties of the first tts that has default properties.
  * @param {string} property Name of property.
  * @return {?number} The default value.
  */
 cvox.TtsInterface.prototype.getDefaultProperty = function(property) { };