[PATCH xserver] present/wnmd: Preserve window pixmap's screen_x/y on flip

[Adam Jackson]

On Thu, 2018-06-07 at 18:27 +0200, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
> 
> The incorrect values could result in the new pixmap's contents
> getting corrupted down the line.
> 
> Bugzilla: https://bugs.freedesktop.org/106841
> Fixes: 029608dd8020 "present: Add window flip mode"
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

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

- ajax