[gnome-shell] layout: Fix old event removal

[Jasper St. Pierre <jstpierre src gnome org>]

commit 001bbd36f55f8f097b9fe7f72e7b7b1fc931f3c5
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Feb 14 21:21:20 2013 -0500

    layout: Fix old event removal
    
    If we increment our index variable while looping, this means that
    firstNewEvent will be one higher than it should. With a length 1
    array, all events will be removed, so this has a cascading effect
    that events will not be stored at all.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=693854

 js/ui/layout.js |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/layout.js b/js/ui/layout.js
index 26d2393..cae7f81 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -1176,8 +1176,9 @@ const PressureBarrier = new Lang.Class({
         // and then chop events after that off.
         let i = 0;
         while (i < this._barrierEvents.length) {
-            if (!this._isBarrierEventTooOld(this._barrierEvents[i++]))
+            if (!this._isBarrierEventTooOld(this._barrierEvents[i]))
                 break;
+            i++;
         }
 
         let firstNewEvent = i;