Replace ButtonDropDown menu implementation (Menu2) with MenuItemView.

views/controls/button/button_dropdown.h

Index: views/controls/button/button_dropdown.h
diff --git a/views/controls/button/button_dropdown.h b/views/controls/button/button_dropdown.h
index 9e8785c22c4a74885e7ab721bc6840867141dffb..0728aa627578e15dca812e830e0904832d9490f2 100644
--- a/views/controls/button/button_dropdown.h
+++ b/views/controls/button/button_dropdown.h
@@ -8,7 +8,10 @@
 
 #include "base/task.h"
 #include "views/controls/button/image_button.h"
-#include "views/controls/menu/menu_2.h"
+
+namespace ui {
+class MenuModel;
+}  // namespace ui
 
 namespace views {
 
@@ -51,7 +54,6 @@ class ButtonDropDown : public ImageButton {
 
   // The model that populates the attached menu.
   ui::MenuModel* model_;
-  scoped_ptr<Menu2> menu_;
 
   // Y position of mouse when left mouse button is pressed
   int y_position_on_lbuttondown_;