After uninstall, remove last item in Launcher folder

ui/app_list/app_list_model.h

 // 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.
 
 #ifndef UI_APP_LIST_APP_LIST_MODEL_H_
 #define UI_APP_LIST_APP_LIST_MODEL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 89 matching lines @@
   // |folder_id| is empty. The item will be inserted before |position| or at
   // the end of the list if |position| is invalid. Note: |position| is copied
   // in case it refers to the containing folder which may get deleted. See also
   // the comment for RemoveItemFromFolder. Returns true if the item was moved.
   // NOTE: This should only be called by the View code (not the sync code); it
   // enforces folder restrictions (e.g. the source folder can not be type OEM).
   bool MoveItemToFolderAt(AppListItem* item,
                           const std::string& folder_id,
                           syncer::StringOrdinal position);
 
+  // Wrapper around DeleteItem() which will also notify its parent folder; this
+  // allows observer to clean up folder with a single item remaining.

[stevenjb, 2015/03/23 19:34:30]

nit: observers, folders

[Greg Levin, 2015/03/23 22:04:50]

Done.

+  void DeleteUninstalledItem(const std::string& id);
+
   // Sets the position of |item| either in |top_level_item_list_| or the folder
   // specified by |item|->folder_id(). If |new_position| is invalid, move the
   // item to the end of the list.
   void SetItemPosition(AppListItem* item,
                        const syncer::StringOrdinal& new_position);
 
   // Sets the name of |item| and notifies observers.
   void SetItemName(AppListItem* item, const std::string& name);
 
   // Sets the name and short name of |item| and notifies observers.
@@ skipping 104 matching lines @@
 
   // The current number of subpages the custom launcher page has pushed.
   int custom_launcher_page_subpage_depth_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListModel);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_MODEL_H_