Make changing your layout manager work.

sky/engine/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 953 matching lines @@
 
 void Element::setLayoutManager(PassOwnPtr<LayoutCallback> callback)
 {
     bool isAlreadyCustomLayout = renderer() && renderer()->isRenderCustomLayout();
     bool requiresCustomLayout = callback;
     if (requiresCustomLayout != isAlreadyCustomLayout) {
         // We don't go through the normal reattach codepaths because
         // those are all tied to changes to the RenderStyle.
         markAncestorsWithChildNeedsStyleRecalc();
         detach();
+    } else if (callback.get() != m_layoutManager) {
+        setNeedsLayout();
     }
     m_layoutManager = callback;
 }
 
 void Element::childrenChanged(const ChildrenChange& change)
 {
     ContainerNode::childrenChanged(change);
 
     if (ElementShadow* shadow = this->shadow())
         shadow->setNeedsDistributionRecalc();
@@ skipping 660 matching lines @@
         return false;
     if (treeScope().scopedStyleResolver().hasSelectorForId(idValue))
         return true;
     // Host rules could also have effects.
     if (ShadowRoot* shadowRoot = this->shadowRoot())
         return shadowRoot->scopedStyleResolver().hasSelectorForId(idValue);
     return false;
 }
 
 } // namespace blink