This event was at various times used for several different purposes. The only
current use is apparently to prevent stale samples from being rendered after
IPin::EndFlush() completes, but in practice there's actually no foolproof way
to prevent this race in the video renderer. On the other hand, as long as the
filter driving the graph can ensure this, there's no need to do so.
Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>