Adding ChromeVox as a component extensions (enabled only for ChromeOS, for no...

chrome/browser/resources/access_chromevox/audio/background/chrome_native_tts_engine.js

+// Copyright (c) 2011 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 Sends Text-To-Speech commands to the TTS that is
+ * embedded in ChromeOS.
+ */
+
+goog.provide('cvox.ChromeVoxChromeOsTtsEngine');
+
+goog.require('cvox.AbstractTts');
+
+/**
+ * @constructor
+ * @extends {cvox.AbstractTts}
+ */
+cvox.ChromeVoxChromeOsTtsEngine = function() {
+  //Inherit AbstractTts
+  cvox.AbstractTts.call(this);
+};
+goog.inherits(cvox.ChromeVoxChromeOsTtsEngine, cvox.AbstractTts);
+
+/**
+ * @return {string} The human-readable name of the speech engine.
+ */
+cvox.ChromeVoxChromeOsTtsEngine.prototype.getName = function() {
+  return 'Chrome OS Native Speech';
+};
+
+/**
+ * Speaks the given string using the specified queueMode and properties.
+ * @param {string} textString The string of text to be spoken.
+ * @param {number=} queueMode The queue mode: AbstractTts.QUEUE_MODE_FLUSH
+ *        for flush, AbstractTts.QUEUE_MODE_QUEUE for adding to queue.
+ * @param {Object=} properties Speech properties to use for this utterance.
+ */
+cvox.ChromeVoxChromeOsTtsEngine.prototype.speak = function(
+    textString, queueMode, properties) {
+  cvox.ChromeVoxChromeOsTtsEngine.superClass_.speak.call(this, textString,
+      queueMode, properties);
+  if (queueMode === cvox.AbstractTts.QUEUE_MODE_FLUSH) {
+    this.stop();
+  }
+  var mergedProperties = this.mergeProperties(properties);
+  mergedProperties.enqueue = (queueMode === cvox.AbstractTts.QUEUE_MODE_QUEUE);
+  // chrome.experimental.tts.speak is a call directly into Chrome, so
+  // chrome.experimental.tts.speak(textString, null); is NOT the same as
+  // chrome.experimental.tts.speak(textString);
+  //
+  // TODO (chaitanyag): Make the underlying code handle var args so that
+  // properties can be optional and match JS expected behavior of these two
+  // being the same.
+  if (mergedProperties) {
+    chrome.experimental.tts.speak(textString, mergedProperties);
+  } else {
+    chrome.experimental.tts.speak(textString);
+  }
+};
+
+/**
+ * Returns true if the TTS is currently speaking.
+ * @return {boolean} True if the TTS is speaking.
+ */
+cvox.ChromeVoxChromeOsTtsEngine.prototype.isSpeaking = function() {
+  cvox.ChromeVoxChromeOsTtsEngine.superClass_.isSpeaking.call(this);
+  return chrome.experimental.tts.isSpeaking();
+};
+
+/**
+ * Stops speech.
+ */
+cvox.ChromeVoxChromeOsTtsEngine.prototype.stop = function() {
+  cvox.ChromeVoxChromeOsTtsEngine.superClass_.stop.call(this);
+  chrome.experimental.tts.stop();
+};
+