[gtk+] applicationwindow: fix leak of help_overlay

[Matthias Clasen <matthiasc src gnome org>]

commit 353281d9d07ac49082cf2de19d7de33d5eb2e02d
Author: Alan Jenkins <alan christopher jenkins gmail com>
Date:   Wed Oct 12 13:33:39 2016 +0100

    applicationwindow: fix leak of help_overlay
    
    > Due to Gtk+ keeping a reference to the window internally,
    > gtk_window_new() does not return a reference to the caller.
    > To delete a GtkWindow, call gtk_widget_destroy().
    
    Caller(s) aren't expecting a need to delete help_overlay themselves
    once they've installed it.  (E.g. see gtk_application_window_added()).
    
    I didn't notice any direct precedents, but there's a parallel in the
    current implementation of gtk_container_destroy() which uses
    gtk_widget_destroy() on any added widget.
    
    This avoids leaking 100s of kB per window, when I tested nautilus.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=772859

 gtk/gtkapplicationwindow.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkapplicationwindow.c b/gtk/gtkapplicationwindow.c
index 2128f98..3e1e969 100644
--- a/gtk/gtkapplicationwindow.c
+++ b/gtk/gtkapplicationwindow.c
@@ -794,7 +794,12 @@ gtk_application_window_dispose (GObject *object)
 
   g_clear_object (&window->priv->app_menu_section);
   g_clear_object (&window->priv->menubar_section);
-  g_clear_object (&window->priv->help_overlay);
+
+  if (window->priv->help_overlay)
+    {
+      gtk_widget_destroy (GTK_WIDGET (window->priv->help_overlay));
+      g_clear_object (&window->priv->help_overlay);
+    }
 
   G_OBJECT_CLASS (gtk_application_window_parent_class)->dispose (object);
 
@@ -986,6 +991,8 @@ show_help_overlay (GSimpleAction *action,
  * sets up an action with the name win.show-help-overlay to present
  * it.
  *
+ * @window takes resposibility for destroying @help_overlay.
+ *
  * Since: 3.20
  */
 void
@@ -996,8 +1003,7 @@ gtk_application_window_set_help_overlay (GtkApplicationWindow *window,
   g_return_if_fail (help_overlay == NULL || GTK_IS_SHORTCUTS_WINDOW (help_overlay));
 
   if (window->priv->help_overlay)
-    g_signal_handlers_disconnect_by_func (window->priv->help_overlay,
-                                          G_CALLBACK (gtk_widget_hide_on_delete), NULL);
+    gtk_widget_destroy (GTK_WIDGET (window->priv->help_overlay));
   g_set_object (&window->priv->help_overlay, help_overlay);
 
   if (!window->priv->help_overlay)