Fix unexpected error message when quickly select different wallpapers

chrome/browser/resources/chromeos/wallpaper_manager/js/util.js

 // Copyright (c) 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.
 
 var WallpaperUtil = {};
 
 /**
  * Saves value to local storage that associates with key.
  * @param {string} key The key that associates with value.
  * @param {string} value The value to save to local storage.
@@ skipping 40 matching lines @@
  * @param {XMLHttpRequest=} opt_xhr The XMLHttpRequest object.
  */
 WallpaperUtil.fetchURL = function(url, type, onSuccess, onFailure, opt_xhr) {
   var xhr;
   if (opt_xhr)
     xhr = opt_xhr;
   else
     xhr = new XMLHttpRequest();
 
   try {
-    xhr.addEventListener('loadend', function(e) {
+    // Do not use loadend here to handle both success and failure case. It gets
+    // complicated with abortion. Unexpected error message may show up. See
+    // http://crbug.com/242581.
+    xhr.addEventListener('load', function(e) {
       if (this.status == 200) {
         onSuccess(this);
       } else {
         onFailure();
       }
     });
+    xhr.addEventListener('error', onFailure);
     xhr.open('GET', url, true);
     xhr.responseType = type;
     xhr.send(null);
   } catch (e) {
     onFailure();
   }
 };
 
 /**
  * Sets wallpaper to online wallpaper specified by url and layout
@@ skipping 16 matching lines @@
         chrome.wallpaperPrivate.setWallpaper(xhr.response, layout, url,
                                              onSuccess);
         self.saveWallpaperInfo(url, layout,
                                Constants.WallpaperSourceEnum.Online);
       } else {
         onFailure();
       }
     }, onFailure);
   });
 };