[mutter] cursor-renderer: Keep ref to displayed cursor sprite

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

commit a10f35c6133f2351aca1f6f6d0ab7703327c678f
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Jul 31 21:10:34 2020 +0200

    cursor-renderer: Keep ref to displayed cursor sprite
    
    If it'd end up beig the XCursor sprite, it'll be unref:ed by the cursor
    tracker when receiving a XFixesCursorNotify:XFixesDisplayCursorNotify
    X11 event.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1391

 src/backends/meta-cursor-renderer.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/meta-cursor-renderer.c b/src/backends/meta-cursor-renderer.c
index eacbf67244..d3ea5ec216 100644
--- a/src/backends/meta-cursor-renderer.c
+++ b/src/backends/meta-cursor-renderer.c
@@ -238,6 +238,8 @@ meta_cursor_renderer_finalize (GObject *object)
 
   g_clear_signal_handler (&priv->after_paint_handler_id, stage);
 
+  g_clear_object (&priv->displayed_cursor);
+
   G_OBJECT_CLASS (meta_cursor_renderer_parent_class)->finalize (object);
 }
 
@@ -362,7 +364,7 @@ meta_cursor_renderer_set_cursor (MetaCursorRenderer *renderer,
 
   if (priv->displayed_cursor == cursor_sprite)
     return;
-  priv->displayed_cursor = cursor_sprite;
+  g_set_object (&priv->displayed_cursor, cursor_sprite);
 
   meta_cursor_renderer_update_cursor (renderer, cursor_sprite);
 }