[mutter] window-actor: Freeze subsurfaces as well

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

commit 1c1c8b25edf79574bd41e1517b4261d2a91fc7eb
Author: Robert Mader <robert mader posteo de>
Date:   Mon Jun 29 15:15:46 2020 +0200

    window-actor: Freeze subsurfaces as well
    
    In order to prevent glitches in animations, make sure we freeze all
    surfaces of a window actor.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1339

 src/compositor/meta-surface-actor.c |  3 +++
 src/compositor/meta-window-actor.c  | 14 ++++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)
---
diff --git a/src/compositor/meta-surface-actor.c b/src/compositor/meta-surface-actor.c
index 0fa6f64ed7..7d5f2bc5d8 100644
--- a/src/compositor/meta-surface-actor.c
+++ b/src/compositor/meta-surface-actor.c
@@ -545,6 +545,9 @@ meta_surface_actor_set_frozen (MetaSurfaceActor *self,
   MetaSurfaceActorPrivate *priv =
     meta_surface_actor_get_instance_private (self);
 
+  if (priv->frozen == frozen)
+    return;
+
   priv->frozen = frozen;
 
   if (!frozen && priv->pending_damage)
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 3b39ce9ddf..523fff8fb1 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -261,13 +261,15 @@ static void
 meta_window_actor_set_frozen (MetaWindowActor *self,
                               gboolean         frozen)
 {
-  MetaWindowActorPrivate *priv =
-    meta_window_actor_get_instance_private (self);
-
-  if (meta_surface_actor_is_frozen (priv->surface) == frozen)
-    return;
+  ClutterActor *child;
+  ClutterActorIter iter;
 
-  meta_surface_actor_set_frozen (priv->surface, frozen);
+  clutter_actor_iter_init (&iter, CLUTTER_ACTOR (self));
+  while (clutter_actor_iter_next (&iter, &child))
+    {
+      if (META_IS_SURFACE_ACTOR (child))
+        meta_surface_actor_set_frozen (META_SURFACE_ACTOR (child), frozen);
+    }
 
   META_WINDOW_ACTOR_GET_CLASS (self)->set_frozen (self, frozen);
 }