[win32k]

- When we try to call a hook with null hook proc will cause a crash in user32. Add an assertion in win32k in order to catch the problem a bit earlier

svn path=/trunk/; revision=49145

reactos/subsystems/win32/win32k/ntuser/callback.c

@@ -339,6 +339,8 @@ co_IntCallHookProc(INT HookId,
    PANSI_STRING asClassName;
    PTHREADINFO pti;
 
+   ASSERT(Proc);
+
    pti = PsGetCurrentThreadWin32Thread();
    if (pti->TIF_flags & TIF_INCLEANUP)
    {