[gnome-games/wip/exalm/buildable: 1/2] preferences-page: Implement Gtk.Buildable

[Alexander Mikhaylenko <alexm src gnome org>]

commit 80f222aa6ae6e7375aced23e6fd186658a8d0223
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Sun Oct 14 17:25:50 2018 +0500

    preferences-page: Implement Gtk.Buildable
    
    This will be used in the next commit to add a template to PreferencesPage.

 src/ui/preferences-page.vala | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/src/ui/preferences-page.vala b/src/ui/preferences-page.vala
index c92b77d8..f867d16b 100644
--- a/src/ui/preferences-page.vala
+++ b/src/ui/preferences-page.vala
@@ -1,5 +1,11 @@
 // This file is part of GNOME Games. License: GPL-3.0+.
 
-private class Games.PreferencesPage: Gtk.Bin {
+private class Games.PreferencesPage: Gtk.Bin, Gtk.Buildable {
        public PreferencesSubpage subpage { get; protected set; }
+
+       public void add_child (Gtk.Builder builder, Object child, string? type) {
+               var widget = child as Gtk.Widget;
+
+               add (widget);
+       }
 }