mash: Move ownership of ShelfDelegate to WmShell

ash/shelf/shelf.h

Index: ash/shelf/shelf.h
diff --git a/ash/shelf/shelf.h b/ash/shelf/shelf.h
index fab107728e22d381cc6befc4c0cc107ae875b28d..5cc1fed2c84f20606ad574b688373133013cff94 100644
--- a/ash/shelf/shelf.h
+++ b/ash/shelf/shelf.h
@@ -54,7 +54,6 @@ class ASH_EXPORT Shelf {
   static const char kNativeViewName[];
 
   Shelf(ShelfModel* model,
-        ShelfDelegate* delegate,
         WmShelf* wm_shelf,
         ShelfWidget* widget);
   virtual ~Shelf();
@@ -160,7 +159,6 @@ class ASH_EXPORT Shelf {
  private:
   friend class test::ShelfTestAPI;
 
-  ShelfDelegate* delegate_;
   // The shelf controller. Owned by the root window controller.
   WmShelf* wm_shelf_;
   ShelfWidget* shelf_widget_;