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

Source 

@DomName('HTMLKeygenElement.setCustomValidity')
@DocsEditable()
void setCustomValidity(String error) => _blink.BlinkHTMLKeygenElement.instance
    .setCustomValidity_Callback_1_(this, error);