As of https://crrev.com/9e653328e3 the Views framework will apply the "always
on top" (WS_EX_TOPMOST) style by default to widgets created with TYPE_MENU. CEF
uses this type in CefWindowView::CreateWidget to support child windows that are
not clipped to the parent window bounds (currently indicated by returning a
parent window from CefWindowDelegate::GetParentWindow and setting |is_menu| to
true).
Not setting "always on top" shouldn't be a problem except in cases where some
other window is already "always on top" and the child CefWindow is expected to
overlay that window. For this reason any menus created using ShowMenu will
continue to have the "always on top" style.
