[mutter] window-actor/wayland: Remove custom get_paint_volume() vfunc

[verdre <jonasd src gnome org>]

commit d722e59aacf2bec62d523992296a252974131304
Author: Robert Mader <robert mader posteo de>
Date:   Mon Jun 29 14:34:10 2020 +0200

    window-actor/wayland: Remove custom get_paint_volume() vfunc
    
    It doesn't take all children - subsurfaces in this case - into
    account, thus creating glitches if subsurfaces extend outside
    of the toplevel surface.
    
    Further more it doesn't seem to serve any special purpose - it was
    added in f7315c9a36462, a pretty big commit, and no discussion was
    started about the code in question. So it was likely just overlooked
    in the review process.
    
    Closes https://gitlab.gnome.org/GNOME/mutter/-/issues/873
    Closes https://gitlab.gnome.org/GNOME/mutter/-/issues/1316

 src/compositor/meta-window-actor-wayland.c | 26 --------------------------
 1 file changed, 26 deletions(-)
---
diff --git a/src/compositor/meta-window-actor-wayland.c b/src/compositor/meta-window-actor-wayland.c
index a287fdcbac..cab6bbc847 100644
--- a/src/compositor/meta-window-actor-wayland.c
+++ b/src/compositor/meta-window-actor-wayland.c
@@ -141,29 +141,6 @@ meta_window_actor_wayland_set_frozen (MetaWindowActor *actor,
 {
 }
 
-static gboolean
-meta_window_actor_wayland_get_paint_volume (ClutterActor       *actor,
-                                            ClutterPaintVolume *volume)
-{
-  MetaSurfaceActor *surface;
-
-  surface = meta_window_actor_get_surface (META_WINDOW_ACTOR (actor));
-  if (surface)
-    {
-      ClutterActor *surface_actor = CLUTTER_ACTOR (surface);
-      const ClutterPaintVolume *child_volume;
-
-      child_volume = clutter_actor_get_transformed_paint_volume (surface_actor,
-                                                                 actor);
-      if (!child_volume)
-        return FALSE;
-
-      clutter_paint_volume_union (volume, child_volume);
-    }
-
-  return TRUE;
-}
-
 static void
 meta_window_actor_wayland_update_regions (MetaWindowActor *actor)
 {
@@ -173,9 +150,6 @@ static void
 meta_window_actor_wayland_class_init (MetaWindowActorWaylandClass *klass)
 {
   MetaWindowActorClass *window_actor_class = META_WINDOW_ACTOR_CLASS (klass);
-  ClutterActorClass *actor_class = CLUTTER_ACTOR_CLASS (klass);
-
-  actor_class->get_paint_volume = meta_window_actor_wayland_get_paint_volume;
 
   window_actor_class->assign_surface_actor = meta_window_actor_wayland_assign_surface_actor;
   window_actor_class->frame_complete = meta_window_actor_wayland_frame_complete;