[polari] ui: Use GtkHeaderBar's builtin close button

[Florian Müllner <fmuellner src gnome org>]

commit f5a8ef039bb4cd5d72b8ca0ed5446aacb115847a
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Aug 8 00:42:47 2013 +0200

    ui: Use GtkHeaderBar's builtin close button
    
    It's new, it makes sense, let's use it.

 data/resources/main-window.ui |   26 +-------------------------
 1 files changed, 1 insertions(+), 25 deletions(-)
---
diff --git a/data/resources/main-window.ui b/data/resources/main-window.ui
index 9994c6b..5ff61db 100644
--- a/data/resources/main-window.ui
+++ b/data/resources/main-window.ui
@@ -104,6 +104,7 @@
           <object class="GtkHeaderBar" id="titlebar_right">
             <property name="visible">True</property>
             <property name="hexpand">True</property>
+            <property name="show_close_button">True</property>
             <!-- 6 should be the default value, but we set it explicitly
                  to make sure it matches the value used in the left group
                  (where we move the padding to the first element instead to
@@ -149,31 +150,6 @@
                 <property name="pack_type">end</property>
               </packing>
             </child>
-            <child>
-              <object class="GtkButton" id="button4">
-                <property name="visible">True</property>
-                <property name="can_focus">True</property>
-                <property name="focus_on_click">False</property>
-                <property name="halign">center</property>
-                <property name="valign">center</property>
-                <property name="action_name">app.quit</property>
-                <property name="relief">none</property>
-                <style>
-                  <class name="image-button"/>
-                </style>
-                <child>
-                  <object class="GtkImage" id="image4">
-                    <property name="visible">True</property>
-                    <property name="can_focus">False</property>
-                    <property name="icon_name">window-close-symbolic</property>
-                    <property name="icon_size">1</property>
-                  </object>
-                </child>
-              </object>
-              <packing>
-                <property name="pack_type">end</property>
-              </packing>
-            </child>
           </object>
         </child>
       </object>