Change LayoutState to be stack-allocated

Source/core/rendering/RenderBlock.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 21 matching lines @@
 #include "core/rendering/style/ShapeValue.h"
 #include "platform/text/TextBreakIterator.h"
 #include "platform/text/TextRun.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/OwnPtr.h"
 
 namespace WebCore {
 
 class BasicShape;
 class BidiContext;
-class LayoutStateMaintainer;
 class LineLayoutState;
 class RenderInline;
 class RenderText;
 
 struct BidiRun;
 struct PaintInfo;
 class LineInfo;
 class RenderRubyRun;
 class WordMeasurement;
 
@@ skipping 496 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of RenderBlock and into RenderBlockFlow.
     friend class RenderBlockFlow;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlock, isRenderBlock());
 
 } // namespace WebCore
 
 #endif // RenderBlock_h