[gnome-boxes] app-window: Closing window removes it from collection

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit df7751b4e6f631d2f6d1375706845651f9e51d8d
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sun Aug 3 16:16:02 2014 +0200

    app-window: Closing window removes it from collection
    
    This is needed to make multiple windows possible.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734486

 src/app-window.vala |    7 ++++++-
 src/app.vala        |   18 ++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletions(-)
---
diff --git a/src/app-window.vala b/src/app-window.vala
index 5e53308..88b2de1 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -305,6 +305,11 @@ private class Boxes.AppWindow: Gtk.ApplicationWindow, Boxes.UI {
 
     [GtkCallback]
     private bool on_delete_event () {
-        return App.app.quit_app ();
+        return_if_fail (current_item == null || current_item is Machine);
+
+        if (current_item != null)
+            (current_item as Machine).window = null;
+
+        return App.app.remove_window (this);
     }
 }
diff --git a/src/app.vala b/src/app.vala
index 0007331..81eb63a 100644
--- a/src/app.vala
+++ b/src/app.vala
@@ -499,4 +499,22 @@ private class Boxes.App: Gtk.Application {
 
         return window;
     }
+
+    public new bool remove_window (AppWindow window) {
+        var initial_windows_count = windows.length ();
+
+        if (window.current_item != null)
+            (window.current_item as Machine).window = null;
+
+        window.hide ();
+        windows.remove (window);
+        base.remove_window (window);
+
+        if (windows.length () == 0)
+            return quit_app ();
+
+        notify_property ("main-window");
+
+        return initial_windows_count != windows.length ();
+    }
 }