[gnome-sudoku/vala-port] Use GtkHeaderBar for the main window

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 6e2b701cf5e94cf063081706b99ac5f008716ea7
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Feb 24 09:29:22 2014 -0600

    Use GtkHeaderBar for the main window
    
    Still needed on the print dialogs.
    
    Also, do not hide the titlebar when maximized.

 configure.ac         |    2 +-
 data/gnome-sudoku.ui |   11 +++++++++--
 2 files changed, 10 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index d7148d3..90709ae 100644
--- a/configure.ac
+++ b/configure.ac
@@ -15,7 +15,7 @@ dnl ###########################################################################
 dnl Dependencies
 dnl ###########################################################################
 
-GTK_REQUIRED=3.4.0
+GTK_REQUIRED=3.10.0
 
 PKG_CHECK_MODULES(GNOME_SUDOKU, [
   gio-2.0
diff --git a/data/gnome-sudoku.ui b/data/gnome-sudoku.ui
index 600e09b..ba1bc34 100644
--- a/data/gnome-sudoku.ui
+++ b/data/gnome-sudoku.ui
@@ -1,9 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <interface>
-  <!-- interface-requires gtk+ 3.4 -->
+  <!-- interface-requires gtk+ 3.10 -->
   <object class="GtkApplicationWindow" id="sudoku_app">
         <property name="title" translatable="yes">Sudoku</property>
-        <property name="hide_titlebar_when_maximized">True</property>
+        <child type="titlebar">
+            <object class="GtkHeaderBar" id="headerbar">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="show_close_button">True</property>
+                <property name="title" translatable="yes">Sudoku</property>
+            </object>
+        </child>
         <child>
             <object class="GtkBox" id="main_box">
                 <property name="visible">True</property>