messageTray: Reduce the scroll view fade

https://bugzilla.gnome.org/show_bug.cgi?id=662226

data/theme/gnome-shell.css

@@ -1217,6 +1217,7 @@ StTooltip StLabel {
 
 #notification-scrollview {
     max-height: 10em;
+    -st-vfade-offset: 24px;
 }
 
 #notification-scrollview > .top-shadow, #notification-scrollview > .bottom-shadow {

js/ui/messageTray.js

@@ -597,8 +597,7 @@ Notification.prototype = {
         this._table.add_style_class_name('multi-line-notification');
         this._scrollArea = new St.ScrollView({ name: 'notification-scrollview',
                                                vscrollbar_policy: this._scrollPolicy,
-                                               hscrollbar_policy: Gtk.PolicyType.NEVER,
-                                               style_class: 'vfade' });
+                                               hscrollbar_policy: Gtk.PolicyType.NEVER });
         this._table.add(this._scrollArea, { row: 1,
                                             col: 2 });
         this._updateLastColumnSettings();