[PATCH 0/1] MR3147: winemac.drv: Don't expect an internal driver message to set last error.

[Tim Clem (＠tclem)]

NtUserMessageCall(..., NtUserSendDriverMessage) does not ensure the
validity of the hwnd, so this check will incorrectly fail if the
last error was ERROR_INVALID_WINDOW_HANDLE by coincidence. The
notify_owner call immediately following this code will catch a
destroyed owner hwnd.