[gnome-contacts] App: Ensure Hdy.TitleBar is loaded on startup

[Niels De Graef <nielsdg src gnome org>]

commit 19a62dc4c6c70263722c34732bd34001e112f23c
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Wed Oct 17 14:07:39 2018 +0200

    App: Ensure Hdy.TitleBar is loaded on startup
    
    This is needed as we will use it in the next commit in a GtkBuilder
    descriptor.

 src/contacts-app.vala | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/contacts-app.vala b/src/contacts-app.vala
index d577ae1..47e99ac 100644
--- a/src/contacts-app.vala
+++ b/src/contacts-app.vala
@@ -325,6 +325,7 @@ public class Contacts.App : Gtk.Application {
     // Ensure the following types are loaded on startup, which is needed for
     // them to be instanciable by GtkBuilder.
     typeof (HeaderGroup).ensure ();
+    typeof (TitleBar).ensure ();
   }
 
   public void load_styling () {