Add tiles to the experimental app list start page.

ui/app_list/app_list_model.cc

 // 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.
 
 #include "ui/app_list/app_list_model.h"
 
 #include <string>
 
 #include "ui/app_list/app_list_folder_item.h"
 #include "ui/app_list/app_list_item.h"
@@ skipping 216 matching lines @@
   AppListItem* item = FindItem(id);
   if (!item)
     return;
   if (!item->IsInFolder()) {
     DCHECK_EQ(0u, item->ChildItemCount())
         << "Invalid call to DeleteItem for item with children: " << id;
     FOR_EACH_OBSERVER(AppListModelObserver,
                       observers_,
                       OnAppListItemWillBeDeleted(item));
     top_level_item_list_->DeleteItem(id);
+    FOR_EACH_OBSERVER(AppListModelObserver, observers_, OnAppListItemDeleted());
     return;
   }
   AppListFolderItem* folder = FindFolderItem(item->folder_id());
   DCHECK(folder) << "Folder not found for item: " << item->ToDebugString();
   scoped_ptr<AppListItem> child_item = RemoveItemFromFolder(folder, item);
   DCHECK_EQ(item, child_item.get());
   FOR_EACH_OBSERVER(AppListModelObserver,
                     observers_,
                     OnAppListItemWillBeDeleted(item));
   child_item.reset();  // Deletes item.
+  FOR_EACH_OBSERVER(AppListModelObserver, observers_, OnAppListItemDeleted());
 }
 
 void AppListModel::NotifyExtensionPreferenceChanged() {
   for (size_t i = 0; i < top_level_item_list_->item_count(); ++i)
     top_level_item_list_->item_at(i)->OnExtensionPreferenceChanged();
 }
 
 // Private methods
 
 void AppListModel::OnListItemMoved(size_t from_index,
@@ skipping 70 matching lines @@
   scoped_ptr<AppListItem> result = folder->item_list()->RemoveItem(item->id());
   result->set_folder_id("");
   if (folder->item_list()->item_count() == 0) {
     DVLOG(2) << "Deleting empty folder: " << folder->ToDebugString();
     DeleteItem(folder_id);
   }
   return result.Pass();
 }
 
 }  // namespace app_list