[gnome-nibbles] Use a GtkHeaderBar

[Michael Catanzaro <mcatanzaro src gnome org>]

commit f6f090fc3b747896ca26686a21f42bd0e3d78395
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun Feb 2 19:12:50 2014 -0600

    Use a GtkHeaderBar
    
    https://bugzilla.gnome.org/show_bug.cgi?id=722226

 src/main.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/src/main.c b/src/main.c
index 6a680cb..778402a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -581,6 +581,7 @@ static void
 activate (GtkApplication* app,
           gpointer        user_data)
 {
+  GtkWidget *headerbar;
   GtkWidget *window;
   GtkWidget *label;
   GdkGeometry size_hints = {
@@ -594,8 +595,15 @@ activate (GtkApplication* app,
 
   GtkBuilder *builder;
 
+  headerbar = gtk_header_bar_new ();
+  gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (headerbar), TRUE);
+  gtk_header_bar_set_title (GTK_HEADER_BAR (headerbar), _("Nibbles"));
+  gtk_widget_show (headerbar);
+
   window = gtk_application_window_new (app);
 
+  gtk_window_set_titlebar (GTK_WINDOW (window), headerbar);
+
   gtk_window_set_geometry_hints (GTK_WINDOW (window),
                     window,
                     &size_hints,