[gtk/wip/chergert/quartz4u] macos: remove observer during finalize

[Christian Hergert <chergert src gnome org>]

commit 449264d71a09a7e39b2f77cc0c8ab58f773a5b83
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 5 16:38:46 2020 -0700

    macos: remove observer during finalize

 gdk/macos/gdkmacosdisplay.c | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/gdk/macos/gdkmacosdisplay.c b/gdk/macos/gdkmacosdisplay.c
index 37d45f027a..c3ff6f5d26 100644
--- a/gdk/macos/gdkmacosdisplay.c
+++ b/gdk/macos/gdkmacosdisplay.c
@@ -535,6 +535,11 @@ gdk_macos_display_finalize (GObject *object)
 {
   GdkMacosDisplay *self = (GdkMacosDisplay *)object;
 
+  CFNotificationCenterRemoveObserver (CFNotificationCenterGetDistributedCenter (),
+                                      self,
+                                      CFSTR ("NSApplicationDidChangeScreenParametersNotification"),
+                                      NULL);
+
   g_clear_pointer (&self->frame_source, g_source_unref);
   g_clear_pointer (&self->monitors, g_ptr_array_unref);
   g_clear_pointer (&self->name, g_free);