[mutter/cherry-pick-4145fbba] clutter/timeline: Clear stage view listener when actor destroyed

[Jonas Ådahl <jadahl src gnome org>]

commit 78c61f557f7c3ff6b604bcb6142d9fed143b50cf
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Feb 8 17:34:00 2021 +0000

    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>
    
    
    (cherry picked from commit 4145fbbae4deb2de830c00a386324929b2ae0d5e)

 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 23392fc99d..f7b9b98a75 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;
 }