nsClassList(const nsClassList& aCopy) : mAtom(aCopy.mAtom),
nsClassList(nsIAtom* aAtom) : mAtom(aAtom),
  nsClassList(const nsClassList& aCopy)    : mAtom(aCopy.mAtom),      mNext(nsnull)  {    MOZ_COUNT_CTOR(nsClassList);    NS_IF_ADDREF(mAtom);    if (aCopy.mNext) {      mNext = new nsClassList(*(aCopy.mNext));    }  }