[gtk+] Avoid an X error

[Matthias Clasen <matthiasc src gnome org>]

commit b94f30bb64bd84ad62b4451c88aeca1f06a1959a
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jan 8 13:48:10 2016 -0500

    Avoid an X error
    
    We are getting the mime data destroy notify called when we
    destroy the surface in finalize. Trying to set the XSync counters
    at this time is a) pointless and b) yielding an X error because
    the counters have already been destroyed.
    To avoid this, unhook the damage tracking before destroying
    the surface.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760188

 gdk/x11/gdkwindow-x11.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index 6106b28..ffe9776 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -1331,6 +1331,8 @@ gdk_x11_window_destroy (GdkWindow *window,
   if (toplevel)
     gdk_toplevel_x11_free_contents (GDK_WINDOW_DISPLAY (window), toplevel);
 
+  unhook_surface_changed (window);
+
   if (impl->cairo_surface)
     {
       cairo_surface_finish (impl->cairo_surface);