rv = EndMediaChange();
END_MEDIA_CHANGE(mStyleSheet, doc)
DOMMediaListImpl::SetMediaText(const nsAString& aMediaText){  nsresult rv;  rv = BeginMediaChange();  if (NS_FAILED(rv))    return rv;    rv = SetText(aMediaText);  if (NS_FAILED(rv))    return rv;    rv = EndMediaChange();  return rv;}