[gnome-shell] PopupSliderMenuItem: Add scroll method

[Adel Gadllah <agadllah src gnome org>]

commit 5c25497e16e185be7b131755e15f09db41f1c0ce
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Sun Jun 23 23:59:24 2013 +0200

    PopupSliderMenuItem: Add scroll method
    
    This fixes fallout from 847cb5b972a04e7dc21c362a
    
    https://bugzilla.gnome.org/show_bug.cgi?id=702849

 js/ui/popupMenu.js |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/popupMenu.js b/js/ui/popupMenu.js
index 3332fe9..28d1d26 100644
--- a/js/ui/popupMenu.js
+++ b/js/ui/popupMenu.js
@@ -527,6 +527,10 @@ const PopupSliderMenuItem = new Lang.Class({
 
     get value() {
         return this._slider.value;
+    },
+
+    scroll: function (event) {
+        this._slider.scroll(event);
     }
 });