Typecheck JS files for chrome://extensions

chrome/browser/resources/extensions/extension_error.js

 // Copyright 2013 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.
 
 <include src="extension_error_overlay.js">
 
 cr.define('extensions', function() {
   'use strict';
 
   /**
    * Clone a template within the extension error template collection.
    * @param {string} templateName The class name of the template to clone.
    * @return {HTMLElement} The clone of the template.
    */
   function cloneTemplate(templateName) {
-    return $('template-collection-extension-error').
-        querySelector('.' + templateName).cloneNode(true);
+    return /** @type {HTMLElement} */($('template-collection-extension-error').
+        querySelector('.' + templateName).cloneNode(true));
   }
 
   /**
    * Checks that an Extension ID follows the proper format (i.e., is 32
    * characters long, is lowercase, and contains letters in the range [a, p]).
    * @param {string} id The Extension ID to test.
    * @return {boolean} Whether or not the ID is valid.
    */
   function idIsValid(id) {
     return /^[a-p]{32}$/.test(id);
   }
 
   /**
    * Creates a new ExtensionError HTMLElement; this is used to show a
    * notification to the user when an error is caused by an extension.
    * @param {Object} error The error the element should represent.
    * @constructor
    * @extends {HTMLDivElement}
    */
   function ExtensionError(error) {
     var div = cloneTemplate('extension-error-metadata');
     div.__proto__ = ExtensionError.prototype;
     div.decorate(error);
     return div;
   }
 
   ExtensionError.prototype = {
     __proto__: HTMLDivElement.prototype,
 
-    /** @override */
+    /**
+     * @param {BackendExtensionErrorObject} error
+     * @override
+     */
     decorate: function(error) {
       // Add an additional class for the severity level.
       if (error.level == 0)
         this.classList.add('extension-error-severity-info');
       else if (error.level == 1)
         this.classList.add('extension-error-severity-warning');
       else
         this.classList.add('extension-error-severity-fatal');
 
       var iconNode = document.createElement('img');
@@ skipping 88 matching lines @@
         button.textContent = loadTimeData.getString(message);
         button.isShowingAll = !button.isShowingAll;
       }.bind(this));
     }
   };
 
   return {
     ExtensionErrorList: ExtensionErrorList
   };
 });