[PATCH 6/7] Present: Check for window/fence destroyed when idling pixmaps

[Adam Jackson]

On Thu, 2013-11-07 at 12:15 -0800, Keith Packard wrote:
> A client destroying objects in the middle of an unflip can end up
> having the screen flip window or fence set to NULL in the unflip
> notify path. Check for these and don't try to use those objects.
> 
> Signed-off-by: Keith Packard <keithp at keithp.com>

Reviewed-by: Adam Jackson <ajax at redhat.com>

- ajax