Function reflect_dom_object_with_cx 

pub(crate) fn reflect_dom_object_with_cx<D, T, U>(
    obj: Box<T>,
    global: &U,
    cx: &mut JSContext,
) -> DomRoot<T>
where
    D: DomTypes,
    T: DomObject + DomObjectWrap<D>,
    U: DerivedFrom<D::GlobalScope>,

Create the reflector for a new DOM object and yield ownership to the reflector.