urlmon: Callback can be NULL

[Alexandre Julliard]

Alistair Leslie-Hughes <leslie_alistair at hotmail.com> writes:

> Hi,
>   Changelog:
> 	urlmon: The callback parameter can be null, check pointer before using.

This breaks the tests:

../../../tools/runtest -q -P wine -M urlmon.dll -T ../../.. -p urlmon_test.exe.so stream.c && touch stream.ok
stream.c:210: Test failed: unexpected call OnDataAvailable
stream.c:329: Test failed: IStream_Read failed with error 0x00000001
stream.c:330: Test failed: read data differs from file
make: *** [stream.ok] Error 3

-- 
Alexandre Julliard
julliard at winehq.org