Complete checked state announcements and clarify state usage

chrome/browser/resources/chromeos/chromevox/common/chrome_extension_externs.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 Definitions for the Chromium extensions API used by ChromeVox.
  *
  * @externs
  */
@@ skipping 636 matching lines @@
 chrome.automation.AutomationNode.prototype.markerEnds;
 
 /** @type {boolean} */
 chrome.automation.AutomationNode.prototype.ariaReadonly;
 
 /** @type {chrome.automation.AutomationNode} */
 chrome.automation.AutomationNode.prototype.nextOnLine;
 /** @type {chrome.automation.AutomationNode} */
 chrome.automation.AutomationNode.prototype.previousOnLine;
 
+/** @type {Object<string, string>} */
+chrome.automation.AutomationNode.prototype.htmlAttributes;
 
 /**
  * @extends {chrome.automation.AutomationNode}
  * @constructor
  */
 chrome.automation.AutomationRootNode = function() {};
 
 /**
  * @type {chrome.automation.AutomationNode}
  */
 chrome.automation.AutomationRootNode.prototype.anchorObject;
 
 /**
  * @type {number}
  */
 chrome.automation.AutomationRootNode.prototype.anchorOffset;
 
 /**
  * @type {chrome.automation.AutomationNode}
  */
 chrome.automation.AutomationRootNode.prototype.focusObject;
 
 /**
  * @type {number}
  */
 chrome.automation.AutomationRootNode.prototype.focusOffset;
 
 /** @type {function() : !Object} */
 chrome.app.getDetails;