Add butter bar for wallpapaer manager(show downloading progress or error message)

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

 // Copyright (c) 2012 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.
  *
  * @constructor
  * @param {HTMLElement} dialogDom The DOM node containing the prototypical
  *     extension UI.
  */
 
 function WallpaperManager(dialogDom) {
   this.dialogDom_ = dialogDom;
   this.document_ = dialogDom.ownerDocument;
   this.selectedCategory = null;
-  this.currentButter_ = null;
+  this.butterBar_ = new ButterBar(this.dialogDom_);
   this.customWallpaperData_ = null;
   this.fetchManifest_();
   this.initDom_();
 }
 
 // Anonymous 'namespace'.
 // TODO(bshe): Get rid of anonymous namespace.
 (function() {
 
   /**
@@ skipping 33 matching lines @@
 
   /**
    * Parses a string as manifest(JSON). Sets manifest to an empty object if a
    * parsing exception is catched.
    * @param {string} response The string to parse as JSON.
    */
   WallpaperManager.prototype.parseManifest_ = function(response) {
     try {
       this.manifest_ = JSON.parse(response);
     } catch (e) {
-      // TODO(bshe): Shows an error butter bar to notify json parse exception.
+      this.butterBar_.showError_('Failed to parse manifest.');
       this.manifest_ = {};
     }
   };
 
   /**
    * Requests wallpaper manifest file from server.
    */
   WallpaperManager.prototype.fetchManifest_ = function() {
     var xhr = new XMLHttpRequest();
     var locale = navigator.language;
     xhr.open('GET', ManifestBaseURL + locale + '.json', false);
     xhr.send(null);
     // TODO(bshe): We should save the downloaded manifest to local disk. Other
     // components may want to use it (i.e. screen saver).
     if (xhr.status === 200) {
       this.parseManifest_(xhr.responseText);
-    } else if (xhr.status === 404) {
+    } else {
       // Fall back to en locale if current locale is not supported.
       xhr.open('GET', ManifestBaseURL + 'en.json', false);
       xhr.send(null);
       if (xhr.status === 200) {
         this.parseManifest_(xhr.responseText);
+      } else {
+        this.manifest_ = {};
+        this.butterBar_.showError_('Failed to download manifest.');
       }
     }
 
     // TODO(bshe): Fall back to saved manifest if there is a problem fetching
     // manifest from server.
   };
 
   /**
    * One-time initialization of various DOM nodes.
    */
@@ skipping 63 matching lines @@
 
     if (this.wallpaperRequest_)
       this.wallpaperRequest_.abort();
     // TODO(bshe): XMLHttpRequest may be cancelled by window.close(). We should
     // either wait for response before closing window or use an extension
     // background page to get response afte window closed.
     this.wallpaperRequest_ = new XMLHttpRequest();
     this.wallpaperRequest_.open('GET', wallpaperURL, true);
     this.wallpaperRequest_.responseType = 'arraybuffer';
     this.wallpaperRequest_.send(null);
+    this.butterBar_.setRequest(this.wallpaperRequest_);
     var self = this;
     this.wallpaperRequest_.addEventListener('load', function(e) {
-      //TODO(bshe): Add error handling code.
       if (self.wallpaperRequest_.status === 200) {
         var image = self.wallpaperRequest_.response;
         chrome.wallpaperPrivate.setWallpaper(image,
                                              selectedItem.layout,
                                              wallpaperURL);
+      } else {
+        // Displays the error text in butter bar.
+        self.butterBar_.showError_(self.wallpaperRequest_.statusText);
       }
       self.wallpaperRequest_ = null;
     });
     this.setWallpaperAttribution_(selectedItem);
   };
 
   /**
    * Set attributions of wallpaper with given URL. If URL is not valid, clear
    * the attributions.
    * @param {{baseURL: string, dynamicURL: string, layout: string,
@@ skipping 150 matching lines @@
             authorWebsite: this.manifest_.wallpaper_list[key].author_website
           };
           wallpapersDataModel.push(wallpaperInfo);
         }
       }
       this.wallpaperGrid_.dataModel = wallpapersDataModel;
     }
   };
 
 })();