Protect AppListItemList Add/Remove and fix sync bugs

ui/app_list/app_list_item.h

 // Copyright 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.
 
 #ifndef UI_APP_LIST_APP_LIST_ITEM_H_
 #define UI_APP_LIST_APP_LIST_ITEM_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/observer_list.h"
 #include "sync/api/string_ordinal.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace ui {
 class MenuModel;
 }
 
 namespace app_list {
 
 class AppListItemList;
 class AppListItemListTest;
 class AppListItemObserver;
+class AppListModel;
 
 // AppListItem provides icon and title to be shown in a AppListItemView
 // and action to be executed when the AppListItemView is activated.
 class APP_LIST_EXPORT AppListItem {
  public:
   explicit AppListItem(const std::string& id);
   virtual ~AppListItem();
 
   void SetIcon(const gfx::ImageSkia& icon, bool has_shadow);
   const gfx::ImageSkia& icon() const { return icon_; }
@@ skipping 31 matching lines @@
   // Note the returned menu model is owned by this item.
   virtual ui::MenuModel* GetContextMenuModel();
 
   // Utility functions for sync integration tests.
   virtual bool CompareForTest(const AppListItem* other) const;
   virtual std::string ToDebugString() const;
 
  protected:
   friend class AppListItemList;
   friend class AppListItemListTest;
+  friend class AppListModel;
 
   void set_position(const syncer::StringOrdinal& new_position) {
     DCHECK(new_position.IsValid());
     position_ = new_position;
   }
 
  private:
   friend class AppListModelTest;
 
   const std::string id_;
   syncer::StringOrdinal position_;
   gfx::ImageSkia icon_;
   bool has_shadow_;
   std::string title_;
   std::string full_name_;
   bool highlighted_;
   bool is_installing_;
   int percent_downloaded_;
 
   ObserverList<AppListItemObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListItem);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_ITEM_H_