[mutter] wayland/subsurface: Check if actor exists before unparenting

[Jonas Ådahl <jadahl src gnome org>]

commit 66ae09b670602347e34ae39eba2f5410ccb28007
Author: Robert Mader <robert mader posteo de>
Date:   Sun Oct 6 12:11:19 2019 +0200

    wayland/subsurface: Check if actor exists before unparenting
    
    When we call the subsurface destructor the actor might be gone already.
    Check first, like we do in other places, to avoid warnings.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/829

 src/wayland/meta-wayland-subsurface.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/src/wayland/meta-wayland-subsurface.c b/src/wayland/meta-wayland-subsurface.c
index 6d181150c..6abfde19f 100644
--- a/src/wayland/meta-wayland-subsurface.c
+++ b/src/wayland/meta-wayland-subsurface.c
@@ -304,9 +304,13 @@ meta_wayland_subsurface_class_init (MetaWaylandSubsurfaceClass *klass)
 static void
 unparent_actor (MetaWaylandSurface *surface)
 {
-  ClutterActor *actor = CLUTTER_ACTOR (meta_wayland_surface_get_actor (surface));
+  ClutterActor *actor;
   ClutterActor *parent_actor;
 
+  actor = CLUTTER_ACTOR (meta_wayland_surface_get_actor (surface));
+  if (!actor)
+    return;
+
   parent_actor = clutter_actor_get_parent (actor);
   clutter_actor_remove_child (parent_actor, actor);
 }