Unchecking the "Surprise Me" checkbox should go back previous wallpaper before "Surprise Me" was tu…

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 177 matching lines @@
       $('wallpaper-grid').classList.add('image-picker-offline');
     });
   };
 
   /**
    * Toggle surprise me feature of wallpaper picker. It fires an storage
    * onChanged event. Event handler for that event is in event_page.js.
    * @private
    */
   WallpaperManager.prototype.toggleSurpriseMe_ = function() {
+    var self = this;
     var checkbox = $('surprise-me').querySelector('#checkbox');
     var shouldEnable = !checkbox.classList.contains('checked');
     WallpaperUtil.saveToStorage(Constants.AccessSurpriseMeEnabledKey,
                                 shouldEnable, true, function() {
       if (chrome.runtime.lastError == null) {
           if (shouldEnable) {
             checkbox.classList.add('checked');
           } else {
+            // Unchecking the "Surprise me" checkbox falls back to the previous
+            // wallpaper before "Surprise me" was turned on.
+            self.setSelectedWallpaper_(self.wallpaperGrid_.activeItem_);
+            self.onWallpaperChanged_(self.wallpaperGrid_.activeItem_,
+                                     self.currentWallpaper_);
             checkbox.classList.remove('checked');
           }
           $('categories-list').disabled = shouldEnable;
           $('wallpaper-grid').disabled = shouldEnable;
         } else {
           // TODO(bshe): show error message to user.
           console.error('Failed to save surprise me option to chrome storage.');
         }
     });
   };
@@ skipping 759 matching lines @@
     var categoriesList = this.categoriesList_;
     var selectedIndex = categoriesList.selectionModel.selectedIndex;
     if (selectedIndex == -1)
       return;
     var selectedListItem = categoriesList.getListItemByIndex(selectedIndex);
     var bar = $('bar');
     bar.style.left = selectedListItem.offsetLeft + 'px';
     bar.style.width = selectedListItem.offsetWidth + 'px';
 
     var wallpapersDataModel = new cr.ui.ArrayDataModel([]);
-    var selectedItem;
+    var selectedItem = null;
     if (selectedListItem.custom) {
       this.document_.body.setAttribute('custom', '');
       var errorHandler = this.onFileSystemError_.bind(this);
       var toArray = function(list) {
         return Array.prototype.slice.call(list || [], 0);
       };
 
       var self = this;
       var processResults = function(entries) {
         for (var i = 0; i < entries.length; i++) {
@@ skipping 25 matching lines @@
             selectedItem = wallpapersDataModel.item(i);
         }
         var lastElement = {
             baseURL: '',
             layout: '',
             source: Constants.WallpaperSourceEnum.AddNew,
             availableOffline: true
         };
         wallpapersDataModel.push(lastElement);
         self.wallpaperGrid_.dataModel = wallpapersDataModel;
-        self.wallpaperGrid_.selectedItem = selectedItem;
-        self.wallpaperGrid_.activeItem = selectedItem;
+        if (selectedItem) {
+          self.wallpaperGrid_.selectedItem = selectedItem;
+          self.wallpaperGrid_.activeItem = selectedItem;
+        }
       };
 
       var success = function(dirEntry) {
         var dirReader = dirEntry.createReader();
         var entries = [];
         // All of a directory's entries are not guaranteed to return in a single
         // call.
         var readEntries = function() {
           dirReader.readEntries(function(results) {
             if (!results.length) {
@@ skipping 32 matching lines @@
           }
           wallpapersDataModel.push(wallpaperInfo);
           var url = this.manifest_.wallpaper_list[key].base_url +
               Constants.HighResolutionSuffix;
           if (url == this.currentWallpaper_) {
             selectedItem = wallpaperInfo;
           }
         }
       }
       this.wallpaperGrid_.dataModel = wallpapersDataModel;
-      this.wallpaperGrid_.selectedItem = selectedItem;
-      this.wallpaperGrid_.activeItem = selectedItem;
+      if (selectedItem) {
+        this.wallpaperGrid_.selectedItem = selectedItem;
+        this.wallpaperGrid_.activeItem = selectedItem;
+      }
     }
   };
 
 })();