[gtk+] window: Correct the property definition for icon

[Matthias Clasen <matthiasc src gnome org>]

commit 8eea3e2ddd7708dec9169d11b55ad8dfbb1dbc51
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 23 07:39:12 2017 +0200

    window: Correct the property definition for icon
    
    cairo surfaces are boxed types, not objects.

 gtk/gtkwindow.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 57cec5d..31d1444 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -926,11 +926,11 @@ gtk_window_class_init (GtkWindowClass *klass)
                             GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
 
   window_props[PROP_ICON] =
-      g_param_spec_object ("icon",
-                           P_("Icon"),
-                           P_("Icon for this window"),
-                          CAIRO_GOBJECT_TYPE_SURFACE,
-                           GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
+      g_param_spec_boxed ("icon",
+                          P_("Icon"),
+                          P_("Icon for this window"),
+                         CAIRO_GOBJECT_TYPE_SURFACE,
+                          GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
 
   /**
    * GtkWindow:mnemonics-visible: