mash: Cleanup ash shelf application menu code.

ash/common/shelf/shelf_window_watcher_item_delegate.h

Index: ash/common/shelf/shelf_window_watcher_item_delegate.h
diff --git a/ash/common/shelf/shelf_window_watcher_item_delegate.h b/ash/common/shelf/shelf_window_watcher_item_delegate.h
index 592ba73516afb1eeb492b97ee7a5e6c859b4a48e..2ce7db5bdcdbb818417398dd420499ccf4838659 100644
--- a/ash/common/shelf/shelf_window_watcher_item_delegate.h
+++ b/ash/common/shelf/shelf_window_watcher_item_delegate.h
@@ -13,7 +13,8 @@ namespace ash {
 
 class WmWindow;
 
-// ShelfItemDelegate for the items created by ShelfWindowWatcher.
+// ShelfItemDelegate for the items created by ShelfWindowWatcher, for example:
+// The Chrome OS settings window, task manager window, and panel windows.
 class ShelfWindowWatcherItemDelegate : public ShelfItemDelegate {
  public:
   ShelfWindowWatcherItemDelegate(ShelfID id, WmWindow* window);
@@ -23,7 +24,7 @@ class ShelfWindowWatcherItemDelegate : public ShelfItemDelegate {
   // ShelfItemDelegate overrides:
   ShelfItemDelegate::PerformedAction ItemSelected(
       const ui::Event& event) override;
-  ui::SimpleMenuModel* CreateApplicationMenu(int event_flags) override;
+  ShelfAppMenuItemList GetAppMenuItems(int event_flags) override;
   void Close() override;
 
   ShelfID id_;