Replace ButtonDropDown menu implementation (Menu2) with MenuItemView.

views/controls/menu/menu_controller.cc

Index: views/controls/menu/menu_controller.cc
diff --git a/views/controls/menu/menu_controller.cc b/views/controls/menu/menu_controller.cc
index a59caacc9ca35f20ff51b2d2618fb68650837243..1b513d104e06257d1cc2d065ff1163eda8fc523c 100644
--- a/views/controls/menu/menu_controller.cc
+++ b/views/controls/menu/menu_controller.cc
@@ -758,8 +758,15 @@ void MenuController::SetSelection(MenuItemView* menu_item,
   }
 
   // Notify the old path it isn't selected.
-  for (size_t i = paths_differ_at; i < current_size; ++i)
+  MenuDelegate* current_delegate =
+      current_path.empty() ? NULL : current_path.front()->GetDelegate();
+  for (size_t i = paths_differ_at; i < current_size; ++i) {
+    if (current_delegate &&
+        current_path[i]->GetType() == MenuItemView::SUBMENU) {
+      current_delegate->WillHideMenu(current_path[i]);
+    }
     current_path[i]->SetSelected(false);
+  }
 
   // Notify the new path it is selected.
   for (size_t i = paths_differ_at; i < new_size; ++i)