Support audio ducking and suspension in ChromeVox

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.
  *
  */
@@ skipping 46 matching lines @@
 /**
  * Called when any utterance starts.
  */
 cvox.TtsCapturingEventListener.prototype.onTtsStart = function() { };
 
 /**
  * Called when any utterance ends.
  */
 cvox.TtsCapturingEventListener.prototype.onTtsEnd = function() { };
 
+/**
+ * Called when any utterance gets interrupted.
+ */
+cvox.TtsCapturingEventListener.prototype.onTtsInterrupted = function() { };
 
 /**
  * @interface
  */
 cvox.TtsInterface = function() { };
 
 /**
  * Speaks the given string using the specified queueMode and properties.
  * @param {string} textString The string of text to be spoken.
  * @param {cvox.QueueMode} queueMode The queue mode to use for speaking.
@@ skipping 39 matching lines @@
  */
 cvox.TtsInterface.prototype.propertyToPercentage = function(property) { };
 
 
 /**
  * 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) { };