Add assert that updateLayoutTree clears dirty bits.

Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 960 matching lines @@
         if (isUserActionElement()) {
             if (hovered())
                 doc.hoveredNodeDetached(this);
             if (inActiveChain())
                 doc.activeChainNodeDetached(this);
             doc.userActionElements().didDetach(this);
         }
     }
 
     setStyleChange(NeedsReattachStyleChange);
-    setChildNeedsStyleRecalc();
 
     document().styleEngine().styleInvalidator().clearInvalidation(*this);
     clearChildNeedsStyleInvalidation();
     clearNeedsStyleInvalidation();
 
 #if ENABLE(ASSERT)
     detachingNode = nullptr;
 #endif
 }
 
@@ skipping 1513 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif