[WIP] do something :-)

Source/core/layout/LayoutBlock.cpp

 /*
  * 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, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 52 matching lines @@
 #include "core/page/Page.h"
 #include "core/paint/BlockPainter.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
 #include "core/style/ComputedStyle.h"
 #include "core/style/ContentData.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/geometry/FloatQuad.h"
 #include "platform/geometry/TransformState.h"
+#include "wtf/SizeAssertions.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/TemporaryChange.h"
 
 using namespace WTF;
 using namespace Unicode;
 
 namespace blink {
 
 using namespace HTMLNames;
 
-struct SameSizeAsLayoutBlock : public LayoutBox {
-    LayoutObjectChildList children;
-    LineBoxList lineBoxes;
-    uint32_t bitfields;
-};
-
-static_assert(sizeof(LayoutBlock) == sizeof(SameSizeAsLayoutBlock), "LayoutBlock should stay small");
+ASSERT_SIZE(LayoutBlock, sizeof(LayoutBox) + 20, sizeof(LayoutBox) + 40);
 
 // This map keeps track of the positioned objects associated with a containing
 // block.
 //
 // This map is populated during layout. It is kept across layouts to handle
 // that we skip unchanged sub-trees during layout, in such a way that we are
 // able to lay out deeply nested out-of-flow descendants if their containing
 // block got laid out. The map could be invalidated during style change but
 // keeping track of containing blocks at that time is complicated (we are in
 // the middle of recomputing the style so we can't rely on any of its
@@ skipping 2785 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink