[gtkmm] Gtk::Application: Simplify make_window_and_run()

[Kjell Ahlstedt <kjellahl src gnome org>]

commit b79cc797a5ce0bfddd5f03198f68c3d91bc1c445
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Tue Mar 22 14:42:36 2022 +0100

    Gtk::Application: Simplify make_window_and_run()
    
    Use Window::set_manage() (via Gtk::make_managed()) and Window::destroy().
    See #114

 gtk/src/application.hg | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)
---
diff --git a/gtk/src/application.hg b/gtk/src/application.hg
index afb723da..c9464c55 100644
--- a/gtk/src/application.hg
+++ b/gtk/src/application.hg
@@ -298,15 +298,9 @@ int Application::make_window_and_run(int argc, char** argv, T_Args&&... args)
   
   signal_activate().connect([this, &args...] () {
     // The created window is managed. Thus, the C++ wrapper is deleted
-    // by Gtk::Object::destroy_notify_() when the window is destroyed.
+    // by Gtk::Object::destroy_notify_() when the C window is destroyed.
     // https://gitlab.gnome.org/GNOME/gtkmm/-/issues/114
-    //TODO: Simplify when Gtk::Window::set_manage() can make a Gtk::Window managed.
-    //auto window = make_managed<T_Window>(std::forward<T_Args>(args)...);
-    auto window = new T_Window(std::forward<T_Args>(args)...);
-    bool was_floating = g_object_is_floating(window->gobj());
-    window->Gtk::Object::set_manage();
-    if (!was_floating && g_object_is_floating(window->gobj()))
-      g_object_ref_sink(window->gobj());
+    auto window = make_managed<T_Window>(std::forward<T_Args>(args)...);
     m_run_window = window;
     add_window(*window);
     window->show();
@@ -315,8 +309,8 @@ int Application::make_window_and_run(int argc, char** argv, T_Args&&... args)
   signal_window_removed().connect([this] (Window* window) {
     if (window == m_run_window)
     {
-      if (window && window->gobj())
-        gtk_window_destroy(window->gobj());
+      if (window)
+        window->destroy();
       m_run_window = nullptr;
     }
   });