font chooser: Move buttons to template

Use the new builder dialog action support.

gtk/gtkfontchooserdialog.c

@@ -151,11 +151,7 @@ gtk_font_chooser_dialog_init (GtkFontChooserDialog *fontchooserdiag)
 
   gtk_widget_init_template (GTK_WIDGET (fontchooserdiag));
   gtk_dialog_set_use_header_bar_from_setting (GTK_DIALOG (fontchooserdiag));
-  gtk_dialog_add_buttons (GTK_DIALOG (fontchooserdiag),
+
-                          _("_Cancel"), GTK_RESPONSE_CANCEL,
-                          _("_Select"), GTK_RESPONSE_OK,
-                          NULL);
-  gtk_dialog_set_default_response (GTK_DIALOG (fontchooserdiag), GTK_RESPONSE_OK);
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
   gtk_dialog_set_alternative_button_order (GTK_DIALOG (fontchooserdiag),
                                            GTK_RESPONSE_OK,

gtk/resources/ui/gtkfontchooserdialog.ui

@@ -28,5 +28,24 @@
         </child>
       </object>
     </child>
+    <child type="action">
+      <object class="GtkButton" id="cancel_button">
+        <property name="visible">True</property>
+        <property name="use_underline">True</property>
+        <property name="label" translatable="yes">_Cancel</property>
+      </object>
+    </child>
+    <child type="action">
+      <object class="GtkButton" id="ok_button">
+        <property name="visible">True</property>
+        <property name="label" translatable="yes">_Select</property>
+        <property name="use_underline">True</property>
+        <property name="can_default">True</property>
+      </object>
+    </child>
+    <action-widgets>
+      <action-widget response="cancel">cancel_button</action-widget>
+      <action-widget response="ok" default="true">ok_button</action-widget>
+    </action-widgets>
   </template>
 </interface>

gtk/resources/ui/gtkfontchooserdialog.ui.h

@@ -1 +1,3 @@
 N_("Select Font");
+N_("_Cancel");
+N_("_Select");