JSBool IsMarked() const {return 0 != (mMemberCount & XPC_NATIVE_IFACE_MARK_FLAG);}
JSBool IsMarked() const {return (JSBool)(((jsword)mJSObject) & 1);}
    JSBool IsMarked() const                    {return 0 != (mMemberCount & XPC_NATIVE_IFACE_MARK_FLAG);}