After uninstall, remove last item in Launcher folder

ui/app_list/app_list_model.cc

Index: ui/app_list/app_list_model.cc
diff --git a/ui/app_list/app_list_model.cc b/ui/app_list/app_list_model.cc
index 0a8e0cd33bfc5b8b006eb65fd62d4dbaf375cb41..468f32414bbae6e21e306da84ae9c633b98a2a55 100644
--- a/ui/app_list/app_list_model.cc
+++ b/ui/app_list/app_list_model.cc
@@ -219,6 +219,25 @@ bool AppListModel::MoveItemToFolderAt(AppListItem* item,
   return true;
 }
 
+void AppListModel::DeleteUninstalledItem(const std::string& id) {
+  AppListItem* item = FindItem(id);
+  if (!item)
+    return;
+  AppListFolderItem* folder = FindFolderItem(item->folder_id());
+  DeleteItem(id);

[stevenjb, 2015/03/25 22:24:00]

What happens if this is the last item in a folder? Can DeleteItem cause the
folder to be deleted? It might be safer to save the folder_id and call
FindFolderItem(folder_id) after calling DeleteItem.

[Greg Levin, 2015/03/26 19:45:11]

Yes, good call.

+
+  // Issue 368111: Upon uninstall of 2nd-to-last folder item, reparent last item
+  // to top and remove folder.
+  if (folder && folder->ChildItemCount() == 1u) {
+    FOR_EACH_OBSERVER(AppListModelObserver, observers_,
+                      OnSingleItemFolderWillBeDeleted());
+
+    // Move last item in model, folder and views will update themselves.
+    AppListItem* last_item = folder->item_list()->item_at(0);
+    MoveItemToFolderAt(last_item, "", folder->position());
+  }
+}
+
 void AppListModel::SetItemPosition(AppListItem* item,
                                    const syncer::StringOrdinal& new_position) {
   if (!item->IsInFolder()) {