Remove more dead app list code.

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 <stddef.h>
 
 #include <string>
@@ skipping 65 matching lines @@
   // Note the returned menu model is owned by this item.
   virtual ui::MenuModel* GetContextMenuModel();
 
   // Returns the item matching |id| contained in this item (e.g. if the item is
   // a folder), or NULL if the item was not found or this is not a container.
   virtual AppListItem* FindChildItem(const std::string& id);
 
   // Returns the number of child items if it has any (e.g. is a folder) or 0.
   virtual size_t ChildItemCount() const;
 
-  // Called when the extension preference changed. Used by ExtensionAppItem
-  // to update icon overlays.
-  virtual void OnExtensionPreferenceChanged();
-
   // Utility functions for sync integration tests.
   virtual bool CompareForTest(const AppListItem* other) const;
   virtual std::string ToDebugString() const;
 
  protected:
   friend class ::FastShowPickler;
   friend class AppListItemList;
   friend class AppListItemListTest;
   friend class AppListModel;
 
@@ skipping 34 matching lines @@
   int percent_downloaded_;
 
   base::ObserverList<AppListItemObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListItem);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_ITEM_H_