Function refresh_missing_text_layout_results 

pub fn refresh_missing_text_layout_results(
    layout: &mut LayoutNode,
    info: &InfoNode,
    viewport: (f32, f32),
)

Supplement: custom flex item layout method

ui_layout measures and positions direct custom flex items but does not call their layout method. Render-time text-flow lookup therefore finds no spans for text directly inside an inline-flex element. Walk the tree and invoke layout for any custom flex item whose result is missing.