[gnome-2048/arnaudb/wip/gtk4: 24/48] HeaderBar is not subclassable anymore.

[Arnaud B. <arnaudb src gnome org>]

commit 94cddf0582ea697cb8dfe79fcdae9d83ac99920a
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Apr 28 09:37:33 2020 +0200

    HeaderBar is not subclassable anymore.

 data/game-headerbar.ui  | 62 ++++++++++++++++++++++++++-----------------------
 src/game-headerbar.vala | 14 +++++++----
 2 files changed, 42 insertions(+), 34 deletions(-)
---
diff --git a/data/game-headerbar.ui b/data/game-headerbar.ui
index 54048bb..6b7d31c 100644
--- a/data/game-headerbar.ui
+++ b/data/game-headerbar.ui
@@ -17,37 +17,41 @@
 -->
 <interface>
   <requires lib="gtk+" version="3.98"/>
-  <template class="GameHeaderBar" parent="GtkHeaderBar">
-    <property name="can-focus">False</property>
-    <!-- Translators: title of the window, displayed in the headerbar -->
-    <property name="title" translatable="yes">GNOME 2048</property>
-    <property name="show-title-buttons">True</property>
+  <template class="GameHeaderBar" parent="GtkWidget">
     <child>
-      <object class="GtkMenuButton" id="_new_game_button">
-        <!-- Translators: button in the headerbar (with a mnemonic that appears pressing Alt) -->
-        <property name="label" translatable="yes">_New Game</property>
-        <property name="valign">center</property>
-        <property name="can-focus">True</property>
-        <property name="receives-default">True</property>
-        <property name="use-underline">True</property>
-        <property name="focus-on-click">False</property>
-      </object>
-    </child>
-    <child type="end">
-      <object class="GtkLabel" id="_score">
+      <object class="GtkHeaderBar" id="_headerbar">
         <property name="can-focus">False</property>
-        <property name="label">0</property>
-      </object>
-    </child>
-    <child type="end">
-      <object class="GtkMenuButton" id="_hamburger_button">
-        <property name="halign">end</property>
-        <property name="valign">center</property>
-        <property name="focus-on-click">False</property>
-        <property name="icon-name">open-menu-symbolic</property>
-        <style>
-          <class name="image-button"/>
-        </style>
+        <!-- Translators: title of the window, displayed in the headerbar -->
+        <property name="title" translatable="yes">GNOME 2048</property>
+        <property name="show-title-buttons">True</property>
+        <child>
+          <object class="GtkMenuButton" id="_new_game_button">
+            <!-- Translators: button in the headerbar (with a mnemonic that appears pressing Alt) -->
+            <property name="label" translatable="yes">_New Game</property>
+            <property name="valign">center</property>
+            <property name="can-focus">True</property>
+            <property name="receives-default">True</property>
+            <property name="use-underline">True</property>
+            <property name="focus-on-click">False</property>
+          </object>
+        </child>
+        <child type="end">
+          <object class="GtkLabel" id="_score">
+            <property name="can-focus">False</property>
+            <property name="label">0</property>
+          </object>
+        </child>
+        <child type="end">
+          <object class="GtkMenuButton" id="_hamburger_button">
+            <property name="halign">end</property>
+            <property name="valign">center</property>
+            <property name="focus-on-click">False</property>
+            <property name="icon-name">open-menu-symbolic</property>
+            <style>
+              <class name="image-button"/>
+            </style>
+          </object>
+        </child>
       </object>
     </child>
   </template>
diff --git a/src/game-headerbar.vala b/src/game-headerbar.vala
index b474e8a..50e1fe5 100644
--- a/src/game-headerbar.vala
+++ b/src/game-headerbar.vala
@@ -21,8 +21,9 @@
 using Gtk;
 
 [GtkTemplate (ui = "/org/gnome/TwentyFortyEight/ui/game-headerbar.ui")]
-private class GameHeaderBar : HeaderBar
+private class GameHeaderBar : Widget
 {
+    [GtkChild] private HeaderBar    _headerbar;
     [GtkChild] private Label        _score;
     [GtkChild] private MenuButton   _new_game_button;
     [GtkChild] private MenuButton   _hamburger_button;
@@ -35,6 +36,9 @@ private class GameHeaderBar : HeaderBar
 
     construct
     {
+        BinLayout layout = new BinLayout ();
+        set_layout_manager (layout);
+
         _hamburger_button.notify ["active"].connect (test_popover_closed);
         _new_game_button.notify ["active"].connect (test_popover_closed);
     }
@@ -57,15 +61,15 @@ private class GameHeaderBar : HeaderBar
 
     internal void clear_subtitle ()
     {
-        set_subtitle (null);
-        set_has_subtitle (false);
+        _headerbar.set_subtitle (null);
+        _headerbar.set_has_subtitle (false);
     }
 
     internal void finished ()
     {
-        set_has_subtitle (true);
+        _headerbar.set_has_subtitle (true);
         /* Translators: subtitle of the headerbar, when the user cannot move anymore */
-        subtitle = _("Game Over");
+        _headerbar.subtitle = _("Game Over");
     }
 
     internal void set_score (Object game, ParamSpec unused)