[MD Feedback] Add feedback to closure compiler.

chrome/browser/resources/md_feedback/feedback.js

 // Copyright 2016 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.
 
 var Feedback = {};
 
 /**
  * API invoked by the browser MdFeedbackWebUIMessageHandler to communicate
  * with this UI.
  */
 Feedback.UI = class {
 
   /**
    * Populates the feedback form with data.
    *
-   * @param {{email: string|undefined,
-   *          url: string|undefined}} data
+   * @param {{email: (string|undefined),
+   *          url: (string|undefined)}} data
    * Parameters in data:
    *   email - user's email, if available.
    *   url - url of the tab the user was on before triggering feedback.
    */
   static setData(data) {
     $('container').email = data['email'];
     $('container').url = data['url'];
   }
 };
 
 /** API invoked by this UI to communicate with the browser WebUI message
  * handler.
  */
 Feedback.BrowserApi = class {
   /**
    * Requests data to initialize the WebUI with.
    * The data will be returned via Feedback.UI.setData.
    */
   static requestData() {
     chrome.send('requestData');
   }
 };
 
 window.addEventListener('DOMContentLoaded', function() {
   Feedback.BrowserApi.requestData();
 });