cvox2: Fix a typo causing the wrong variable to be referenced.

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 418 matching lines @@
 
 
 /**
  * @type {{top: number, left: number, height: number, width: number}}
  */
 chrome.automation.AutomationNode.prototype.location;
 
 
 /**
  * @param {chrome.automation.EventType} eventType
- * @param {function(chrome.automation.AutomationNode) : void} callback
+ * @param {function(!chrome.automation.AutomationEvent) : void} callback
  * @param {boolean} capture
  */
 chrome.automation.AutomationNode.prototype.addEventListener =
     function(eventType, callback, capture) {};
 
 
 /**
  * @param {chrome.automation.EventType} eventType
  * @param {function(chrome.automation.AutomationNode) : void} callback
  * @param {boolean} capture
@@ skipping 57 matching lines @@
 chrome.automation.AutomationNode.prototype.containerLiveAtomic;
 
 /** @type {boolean} */
 chrome.automation.AutomationNode.prototype.containerLiveBusy;
 
 
 /**
  * @param {Object} findParams
  */
 chrome.automation.AutomationNode.prototype.find = function(findParams) {};