nsStringHeader::FromData(data)->Release();
nsStringBuffer::FromData(data)->Release();
ReleaseData( void* data, PRUint32 flags )  {    if (flags & nsSubstring::F_SHARED)      {        nsStringHeader::FromData(data)->Release();      }    else if (flags & nsSubstring::F_OWNED)      {        nsMemory::Free(data);        STRING_STAT_INCREMENT(AdoptFree);      }    // otherwise, nothing to do.  }