[gnome-contacts] Window: Handle window decorations with a Hdy.HeaderGroup

[Niels De Graef <nielsdg src gnome org>]

commit 38e1df7568b9be9d418d0d34b33ab37b5e5f7493
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Wed Oct 17 14:09:05 2018 +0200

    Window: Handle window decorations with a Hdy.HeaderGroup
    
    This avoids to handle the window decoration layout of each heaader bar
    by hand and simplifies the code.

 data/ui/contacts-window.ui |  6 ++++++
 src/contacts-window.vala   | 17 +++++------------
 2 files changed, 11 insertions(+), 12 deletions(-)
---
diff --git a/data/ui/contacts-window.ui b/data/ui/contacts-window.ui
index 12498ad..4c0e736 100644
--- a/data/ui/contacts-window.ui
+++ b/data/ui/contacts-window.ui
@@ -397,4 +397,10 @@
       <widget name="loading_box"/>
     </widgets>
   </object>
+  <object class="HdyHeaderGroup" id="header_group">
+    <headerbars>
+      <headerbar name="left_header"/>
+      <headerbar name="right_header"/>
+    </headerbars>
+  </object>
 </interface>
diff --git a/src/contacts-window.vala b/src/contacts-window.vala
index 3734293..bf0f1ff 100644
--- a/src/contacts-window.vala
+++ b/src/contacts-window.vala
@@ -17,6 +17,7 @@
 
 using Gee;
 using Gtk;
+using Hdy;
 using Folks;
 
 [GtkTemplate (ui = "/org/gnome/Contacts/ui/contacts-window.ui")]
@@ -54,6 +55,9 @@ public class Contacts.Window : Gtk.ApplicationWindow {
   private Button cancel_button;
   [GtkChild]
   private Button done_button;
+  // Somehow needed for the header group to work
+  [GtkChild]
+  private HeaderGroup header_group;
 
   // The 2 panes the window consists of
   private ListPane list_pane;
@@ -96,7 +100,6 @@ public class Contacts.Window : Gtk.ApplicationWindow {
 
     bind_dimension_properties_to_settings ();
     create_contact_pane ();
-    set_headerbar_layout ();
     connect_button_signals ();
     restore_window_size_and_position_from_settings ();
   }
@@ -193,6 +196,7 @@ public class Contacts.Window : Gtk.ApplicationWindow {
     // UI when we're not editing of selecting stuff
     this.add_button.visible
         = this.hamburger_menu_button.visible
+        = this.left_header.show_close_button
         = this.right_header.show_close_button
         = (this.state == UiState.NORMAL || this.state == UiState.SHOWING);
 
@@ -315,17 +319,6 @@ public class Contacts.Window : Gtk.ApplicationWindow {
     list_pane.filter_entry.set_text (query);
   }
 
-  private void set_headerbar_layout () {
-    // Propagate the decoration layout to the separate headerbars, so
-    // that we know, for example, on which side the close button should be.
-    string layout_desc = Gtk.Settings.get_default ().gtk_decoration_layout;
-    string[] tokens = layout_desc.split (":", 2);
-    if (tokens != null) {
-      this.right_header.decoration_layout = ":%s".printf (tokens[1]);
-      this.left_header.decoration_layout = tokens[0];
-    }
-  }
-
   private void connect_button_signals () {
     this.select_cancel_button.clicked.connect (() => { this.state = UiState.NORMAL; });
     this.done_button.clicked.connect (() => stop_editing ());