Function process_resolved_style_request 

pub fn process_resolved_style_request(
    layout_thread: &LayoutThread,
    context: &SharedStyleContext<'_>,
    node: ServoLayoutNode<'_>,
    pseudo: &Option<PseudoElement>,
    property: &PropertyId,
) -> String

Return the resolved value of property for a given (pseudo)element. https://drafts.csswg.org/cssom/#resolved-value