Function create_and_populate_a_resizeobserverentry 

fn create_and_populate_a_resizeobserverentry(
    window: &Window,
    target: &Element,
    observation: &mut ResizeObservation,
    can_gc: CanGc,
) -> DomRoot<ResizeObserverEntry>

https://drafts.csswg.org/resize-observer/#create-and-populate-a-resizeobserverentry