[PATCH 4/4] quartz: Notify EC_USERABORT event when closing video window.

[Zebediah Figura (she/her)]

I notice the documentation also says:

"After sending this event, the filter should reject all samples and not 
send any EC_REPAINT events, until the filter stops and is reset."

That deserves tests (well, the first part, not the EC_REPAINT part; we 
don't handle EC_REPAINT at all yet), and probably implementation changes 
as well.

(It also leads me to wonder if it resets the auto-show mechanism...)