[mutter] clutter/timeline: Add running timeline to frameclock if it changes

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 9b054f4a1b921c9eb49661d75411acfa0eb2309a
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Jun 2 15:06:21 2020 +0200

    clutter/timeline: Add running timeline to frameclock if it changes
    
    It's intended that timelines can change frame clock while running; but
    up until now it'd only add itself if the frame clock was set when
    started.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285

 clutter/clutter/clutter-timeline.c | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/clutter/clutter/clutter-timeline.c b/clutter/clutter/clutter-timeline.c
index dd8451323d..dea89bb385 100644
--- a/clutter/clutter/clutter-timeline.c
+++ b/clutter/clutter/clutter-timeline.c
@@ -2523,8 +2523,14 @@ clutter_timeline_set_frame_clock (ClutterTimeline   *timeline,
   if (priv->frame_clock == frame_clock)
     return;
 
+  if (priv->frame_clock && priv->is_playing)
+    remove_timeline (timeline);
+
   g_set_object (&priv->frame_clock, frame_clock);
 
   g_object_notify_by_pspec (G_OBJECT (timeline),
                             obj_props[PROP_FRAME_CLOCK]);
+
+  if (priv->is_playing)
+    add_timeline (timeline);
 }