[mutter] plugins/default: Clean up tile preview when closing display

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

commit dc1a28c42a717216170e4669c09e06f9ed3edd2c
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Nov 1 13:16:25 2019 +0100

    plugins/default: Clean up tile preview when closing display
    
    On finalize, the preview actor will have been destroyed behind our back;
    avoid that by cleaning up before it's too late.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/912

 src/compositor/plugins/default.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)
---
diff --git a/src/compositor/plugins/default.c b/src/compositor/plugins/default.c
index 42d28ec20..378009006 100644
--- a/src/compositor/plugins/default.c
+++ b/src/compositor/plugins/default.c
@@ -737,9 +737,8 @@ destroy (MetaPlugin *plugin, MetaWindowActor *window_actor)
  * Tile preview private data accessor
  */
 static void
-free_display_tile_preview (gpointer data)
+free_display_tile_preview (DisplayTilePreview *preview)
 {
-  DisplayTilePreview *preview = data;
 
   if (G_LIKELY (preview != NULL)) {
     clutter_actor_destroy (preview->actor);
@@ -747,6 +746,13 @@ free_display_tile_preview (gpointer data)
   }
 }
 
+static void
+on_display_closing (MetaDisplay        *display,
+                    DisplayTilePreview *preview)
+{
+  free_display_tile_preview (preview);
+}
+
 static DisplayTilePreview *
 get_display_tile_preview (MetaDisplay *display)
 {
@@ -769,9 +775,13 @@ get_display_tile_preview (MetaDisplay *display)
       clutter_actor_set_opacity (preview->actor, 100);
 
       clutter_actor_add_child (meta_get_window_group_for_display (display), preview->actor);
-      g_object_set_qdata_full (G_OBJECT (display),
-                               display_tile_preview_data_quark, preview,
-                               free_display_tile_preview);
+      g_signal_connect (display,
+                        "closing",
+                        G_CALLBACK (on_display_closing),
+                        preview);
+      g_object_set_qdata (G_OBJECT (display),
+                          display_tile_preview_data_quark,
+                          preview);
     }
 
   return preview;