[gtk+] Plug some memory leaks

[Timm Bäder <baedert src gnome org>]

commit 29a4f0ce1f7722017f5993a64e2e4a5687d2d4ea
Author: Timm Bäder <mail baedert org>
Date:   Thu Sep 28 20:00:24 2017 +0200

    Plug some memory leaks
    
    Make sure the scroll controllers in GtkComboBox and GtkScrolledWindow
    get destroyed.

 gtk/gtkcombobox.c       |    2 ++
 gtk/gtkscrolledwindow.c |    2 ++
 2 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index dced3d7..633099d 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -2803,6 +2803,8 @@ gtk_combo_box_dispose (GObject* object)
   GtkComboBox *combo_box = GTK_COMBO_BOX (object);
   GtkComboBoxPrivate *priv = combo_box->priv;
 
+  g_clear_object (&priv->scroll_controller);
+
   if (priv->popup_widget)
     {
       /* Stop menu destruction triggering toggle on a now-invalid button */
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 52fbd20..9d89da1 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -2642,6 +2642,8 @@ gtk_scrolled_window_finalize (GObject *object)
   g_clear_object (&priv->swipe_gesture);
   g_clear_object (&priv->long_press_gesture);
   g_clear_object (&priv->pan_gesture);
+  g_clear_object (&priv->scroll_controller);
+
 
   G_OBJECT_CLASS (gtk_scrolled_window_parent_class)->finalize (object);
 }