After uninstall, remove last item in Launcher folder

ui/app_list/app_list_model.h

Index: ui/app_list/app_list_model.h
diff --git a/ui/app_list/app_list_model.h b/ui/app_list/app_list_model.h
index 6c61e71d68ebbed73c6a0c9c23dd195ef2ad5cdf..3b74ce93a7c19071819c5a283086f3827c767e99 100644
--- a/ui/app_list/app_list_model.h
+++ b/ui/app_list/app_list_model.h
@@ -107,6 +107,10 @@ class APP_LIST_EXPORT AppListModel : public AppListItemListObserver {
                           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.