[mutter/wip/carlosg/fix-culling] window-actor: Fix rectangle coordinates in culling

[Carlos Garnacho <carlosg src gnome org>]

commit aae9f3a3e64f7b3cfed45cfd531c740cb9e9ae71
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jul 31 00:23:34 2019 +0200

    window-actor: Fix rectangle coordinates in culling
    
    The cull methods expect regions with 0,0 in the actor top-left corner,
    whereas meta_window_get_frame_rect() returns a rectangle in workarea
    coordinates.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/707

 src/compositor/meta-window-actor.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index d518fec7c..b7261c96f 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -1388,6 +1388,7 @@ meta_window_actor_cull_out (MetaCullable   *cullable,
         {
           cairo_rectangle_int_t rect;
           meta_window_get_frame_rect (priv->window, &rect);
+          rect.x = rect.y = 0;
           cairo_region_subtract_rectangle (unobscured_region, &rect);
         }
     }