[mutter] window-actor: Use vfunc to set the surface actor

[Marco Trevisan <marcotrevi src gnome org>]

commit 4061c8384b72401aa47dd22c34d0fd392abe8a80
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Jun 28 11:14:13 2019 +0200

    window-actor: Use vfunc to set the surface actor
    
    As per commit 80e3c1d set_surface_actor has been added, meant to do different
    things depending on the backend, like connecting to signals under X11.
    
    However, the vfunc isn't ever used, making the X11 surfaces not to react to
    repaint-scheduled signal.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/660

 src/compositor/meta-window-actor.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 1dda678da..12995e567 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -414,7 +414,7 @@ meta_window_actor_update_surface (MetaWindowActor *self)
   else
     surface_actor = NULL;
 
-  set_surface (self, surface_actor);
+  META_WINDOW_ACTOR_GET_CLASS (self)->set_surface_actor (self, surface_actor);
 }
 
 static void
@@ -473,7 +473,7 @@ meta_window_actor_dispose (GObject *object)
 
   g_clear_object (&priv->window);
 
-  set_surface (self, NULL);
+  META_WINDOW_ACTOR_GET_CLASS (self)->set_surface_actor (self, NULL);
 
   G_OBJECT_CLASS (meta_window_actor_parent_class)->dispose (object);
 }