views: use menu border inset to position submenus

Using the border inset directly, instead of trying to recompute it from the
MenuConfig, avoids positioning bugs when the submenu will have a border applied
to it.

Bug: 834934
Change-Id: Ic6c23f7dd5e34b643724c346bb89dac038dd58e4
Reviewed-on: https://chromium-review.googlesource.com/1231736Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592377}

ui/views/controls/menu/menu_controller.cc

@@ -2089,10 +2089,9 @@ gfx::Rect MenuController::CalculateMenuBounds(MenuItemView* item,
     const int right_of_parent =
         item_loc.x() + item->width() - submenu_horizontal_inset;
 
-    int border_size = menu_config.CornerRadiusForMenu(this);
-    if (!border_size)
-      border_size = menu_config.menu_vertical_border_size;
-    menu_bounds.set_y(item_loc.y() - border_size);
+    MenuScrollViewContainer* container =
+        item->GetParentMenuItem()->GetSubmenu()->GetScrollViewContainer();
+    menu_bounds.set_y(item_loc.y() - container->border()->GetInsets().top());
 
     // Assume the menu can be placed in the preferred location.
     menu_bounds.set_x(create_on_right ? right_of_parent : left_of_parent);