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

chrome/browser/resources/access_chromevox/audio/common/local_earcons_manager.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 Bridge that sends earcon messages from content scripts or
+ * other pages to the main background page.
+ */
+
+goog.provide('cvox.LocalEarconsManager');
+
+goog.require('cvox.AbstractEarconsManager');
+
+/**
+ * @constructor
+ * @param {Array} earcons Array of earcon classes.
+ * @param {cvox.AbstractTtsManager} ttsManager A TTS provider.
+ * @extends {cvox.AbstractEarconsManager}
+ */
+cvox.LocalEarconsManager = function(earcons, ttsManager) {
+  //Inherit AbstractEarconsManager
+  cvox.AbstractEarconsManager.call(this);
+
+  this.earcons = earcons;
+  this.ttsManager = ttsManager;
+  this.currentEarcons = null;
+  this.currentEarconsIndex = -1;
+  this.nextEarcons(false);
+};
+goog.inherits(cvox.LocalEarconsManager, cvox.AbstractEarconsManager);
+
+/**
+ * @return {string} The human-readable name of this instance.
+ */
+cvox.LocalEarconsManager.prototype.getName = function() {
+  return 'LocalEarconsManager';
+};
+
+/**
+ * Plays the specified earcon.
+ * @param {number} earcon The index of the earcon to be played.
+ */
+cvox.LocalEarconsManager.prototype.playEarcon = function(earcon) {
+  cvox.LocalEarconsManager.superClass_.playEarcon.call(this, earcon);
+  if (!this.currentEarcons) {
+    return;
+  }
+  this.currentEarcons.playEarcon(earcon);
+};
+
+/**
+ * Switch to the next earcon set and optionally announce its name.
+ * If no earcon sets have been specified this function is a NOOP.
+ * @param {boolean} announce If true, will announce the name of the
+ *     new earcon set.
+ */
+cvox.LocalEarconsManager.prototype.nextEarcons = function(announce) {
+  cvox.LocalEarconsManager.superClass_.nextEarcons.call(this, announce);
+  if (!this.earcons) {
+    return;
+  }
+  this.currentEarcons = null;
+  this.currentEarconsIndex =
+      (this.currentEarconsIndex + 1) % this.earcons.length;
+  try {
+    this.currentEarcons = new this.earcons[this.currentEarconsIndex];
+    console.log('Switching to earcons: ' + this.currentEarcons.getName());
+    if (announce) {
+      this.ttsManager.speak(this.currentEarcons.getName());
+    }
+  } catch (err) {
+    console.log('error switching to earcon #' + this.currentEarconsIndex);
+  }
+};