Call failure callback when failed to set custom wallpaper.

chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_manager.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.
 
 /**
  * WallpaperManager constructor.
  *
  * WallpaperManager objects encapsulate the functionality of the wallpaper
  * manager extension.
  *
@@ skipping 846 matching lines @@
                                                            layout,
                                                            generateThumbnail,
                                                            fileName,
                                                            success,
                                                            failure) {
     var self = this;
     var onFinished = function(opt_thumbnail) {
       if (chrome.runtime.lastError != undefined) {
         self.showError_(chrome.runtime.lastError.message);
         $('set-wallpaper-layout').disabled = true;
+        failure();
       } else {
         success(opt_thumbnail);
       }
     };
 
     chrome.wallpaperPrivate.setCustomWallpaper(wallpaper, layout,
                                                generateThumbnail,
                                                fileName, onFinished);
   };
 
@@ skipping 140 matching lines @@
           }
         }
       }
       this.wallpaperGrid_.dataModel = wallpapersDataModel;
       this.wallpaperGrid_.selectedItem = selectedItem;
       this.wallpaperGrid_.activeItem = selectedItem;
     }
   };
 
 })();