Add ink drop ripple (but no highlight) to comboboxes in harmony.

ui/views/controls/menu/submenu_view.h

Index: ui/views/controls/menu/submenu_view.h
diff --git a/ui/views/controls/menu/submenu_view.h b/ui/views/controls/menu/submenu_view.h
index 269d0fa966c1a249c00fbaea91c7db766e57167a..2e00de54eb2fb9c959ad77dc2c089cc1434b3e54 100644
--- a/ui/views/controls/menu/submenu_view.h
+++ b/ui/views/controls/menu/submenu_view.h
@@ -40,7 +40,8 @@ class MenuControllerTest;
 // MenuScrollViewContainer handles showing as much of the SubmenuView as the
 // screen allows. If the SubmenuView is taller than the screen, scroll buttons
 // are provided that allow the user to see all the menu items.
-class VIEWS_EXPORT SubmenuView : public PrefixDelegate,
+class VIEWS_EXPORT SubmenuView : public View,
+                                 public PrefixDelegate,
                                  public ScrollDelegate {
  public:
   // The submenu's class name.