Add a page to explain earcons in the tutorial

chrome/browser/resources/chromeos/chromevox/host/interface/abstract_earcons.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 Base class for implementing earcons.
  *
  * When adding earcons, please add them to getEarconName and getEarconId.
  *
  */
 
 goog.provide('cvox.AbstractEarcons');
 goog.provide('cvox.Earcon');
+goog.provide('cvox.EarconDescription');
 
 
 /**
  * Earcon names.
  * @enum {string}
  */
 cvox.Earcon = {
   ALERT_MODAL: 'alert_modal',
   ALERT_NONMODAL: 'alert_nonmodal',
   BUTTON: 'button',
@@ skipping 16 matching lines @@
   POP_UP_BUTTON: 'pop_up_button',
   RECOVER_FOCUS: 'recover_focus',
   SELECTION: 'selection',
   SELECTION_REVERSE: 'selection_reverse',
   SKIP: 'skip',
   SLIDER: 'slider',
   WRAP: 'wrap',
   WRAP_EDGE: 'wrap_edge',
 };
 
+/**
+ * Maps a earcon id to a message id description.
+ * Only add mappings for earcons used in ChromeVox Next. This map gets
+ * used to generate tutorial content.
+ * @type {Object<string, string>}
+ */
+cvox.EarconDescription = {
+  alert_modal: 'alert_modal_earcon_description',
+  alert_nonmodal: 'alert_nonmodal_earcon_description',
+  button: 'button_earcon_description',
+  check_off: 'check_off_earcon_description',
+  check_on: 'check_on_earcon_description',
+  editable_text: 'editable_text_earcon_description',
+  invalid_keypress: 'invalid_keypress_earcon_description',
+  link: 'link_earcon_description',
+  listbox: 'listbox_earcon_description',
+  page_start_loading: 'page_start_loading_earcon_description',
+  pop_up_button: 'pop_up_button_earcon_description',
+  slider: 'slider_earcon_description',
+  wrap: 'wrap_earcon_description',
+};
+
 
 /**
  * @constructor
  */
 cvox.AbstractEarcons = function() {
 };
 
 
 /**
  * Public static flag set to enable or disable earcons. Callers should prefer
@@ skipping 29 matching lines @@
 
 
 /**
  * Toggles earcons on or off.
  * @return {boolean} True if earcons are now enabled; false otherwise.
  */
 cvox.AbstractEarcons.prototype.toggle = function() {
   cvox.AbstractEarcons.enabled = !cvox.AbstractEarcons.enabled;
   return cvox.AbstractEarcons.enabled;
 };