1. DomName('HTMLSelectElement.setCustomValidity')
  2. DocsEditable()
void setCustomValidity(String error)

Source 

@DomName('HTMLSelectElement.setCustomValidity')
@DocsEditable()
void setCustomValidity(String error) => _blink.BlinkHTMLSelectElement.instance.setCustomValidity_Callback_1_(unwrap_jso(this), error);