[mutter] window-actor/x11: Freeze/thaw commits on actor freeze/thaw

[Jonas Ådahl <jadahl src gnome org>]

commit d7a7af1ff200626f9cba9abae2eb4b1ed3efa7a5
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Tue Nov 19 14:30:44 2019 +0100

    window-actor/x11: Freeze/thaw commits on actor freeze/thaw
    
    When using Xwayland, if the damage get posted before the X11 window
    manager/compositor has finished repainting the actors, the intermediate
    state will show.
    
    Make sure to hint Xwayland as to when it can post pending damages and
    commit the Wayland buffer using the `freeze_commits()/thaw_commits()`
    API, based on window actor freeze/thaw.
    
    See-also: https://gitlab.gnome.org/GNOME/mutter/merge_requests/855
    See-also: https://gitlab.freedesktop.org/xorg/xserver/merge_requests/316
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/942

 src/compositor/meta-window-actor-x11.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
---
diff --git a/src/compositor/meta-window-actor-x11.c b/src/compositor/meta-window-actor-x11.c
index cc694004a..f5b18414e 100644
--- a/src/compositor/meta-window-actor-x11.c
+++ b/src/compositor/meta-window-actor-x11.c
@@ -98,6 +98,7 @@ struct _MetaWindowActorX11
   gboolean needs_reshape;
   gboolean recompute_focused_shadow;
   gboolean recompute_unfocused_shadow;
+  gboolean is_frozen;
 };
 
 static MetaCullableInterface *cullable_parent_iface;
@@ -1316,6 +1317,18 @@ static void
 meta_window_actor_x11_set_frozen (MetaWindowActor *actor,
                                   gboolean         frozen)
 {
+  MetaWindowActorX11 *actor_x11 = META_WINDOW_ACTOR_X11 (actor);
+  MetaWindow *window = meta_window_actor_get_meta_window (actor);
+
+  if (actor_x11->is_frozen == frozen)
+    return;
+
+  actor_x11->is_frozen = frozen;
+
+  if (frozen)
+    meta_window_x11_freeze_commits (window);
+  else
+    meta_window_x11_thaw_commits (window);
 }
 
 static void