[mutter] clutter/timeline: Clear stage view listener when actor destroyed

[Marge Bot <marge-bot src gnome org>]

commit 4145fbbae4deb2de830c00a386324929b2ae0d5e
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Feb 8 18:34:00 2021 +0100

    clutter/timeline: Clear stage view listener when actor destroyed
    
    We might have a stage view listener attached to the stage itself if the
    actor didn't have a suitable frame clock when the actor was associated
    with the timeline. We'd then listen to stage-views-changed signals on
    the stage itself to be able to attach to a frame clock when one
    appeared.
    
    What went wrong is that if an actor that didn't have a frameclock was
    associated with a timeline, but then destroyed, the timeline would
    disassociate itself from the actor, but it'd still listen on the
    stage-views-changed signal on the stage. This would be in itself
    harmless, until the timeline itself is destroyed, as at this point, it
    wouldn't clean up the stage-views-changed listener on the stage, as it's
    assumed to only be valid when there is an actor attached.
    
    Fix this issue by cleaning up the stage's stage-views-changed listener
    when the actor is destroyed, as we wouldn't be able to make use of it by
    then anyway.
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3323
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1719>

 clutter/clutter/clutter-timeline.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/clutter/clutter/clutter-timeline.c b/clutter/clutter/clutter-timeline.c
index 03b9236454..4637656869 100644
--- a/clutter/clutter/clutter-timeline.c
+++ b/clutter/clutter/clutter-timeline.c
@@ -311,6 +311,7 @@ on_actor_destroyed (ClutterActor    *actor,
 {
   ClutterTimelinePrivate *priv = timeline->priv;
 
+  g_clear_signal_handler (&priv->stage_stage_views_handler_id, priv->stage);
   priv->actor = NULL;
 }