[WIP] do something :-)

Source/core/css/CSSRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2007, 2012 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/css/CSSRule.h"
 
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/StyleRule.h"
 #include "core/css/StyleSheetContents.h"
 #include "platform/NotImplemented.h"
+#include "wtf/SizeAssertions.h"
 
 namespace blink {
 
-struct SameSizeAsCSSRule : public RefCountedWillBeGarbageCollectedFinalized<SameSizeAsCSSRule>, public ScriptWrappable {
-    virtual ~SameSizeAsCSSRule();
-    unsigned char bitfields;
-    void* pointerUnion;
-};
-
-static_assert(sizeof(CSSRule) == sizeof(SameSizeAsCSSRule), "CSSRule should stay small");
+ASSERT_SIZE(CSSRule, 20, 32);
 
 void CSSRule::setCSSText(const String&)
 {
     notImplemented();
 }
 
 const CSSParserContext& CSSRule::parserContext() const
 {
     CSSStyleSheet* styleSheet = parentStyleSheet();
     return styleSheet ? styleSheet->contents()->parserContext() : strictCSSParserContext();
 }
 
 DEFINE_TRACE(CSSRule)
 {
 #if ENABLE(OILPAN)
     // This makes the parent link strong, which is different from the
     // pre-oilpan world, where the parent link is mysteriously zeroed under
     // some circumstances.
     if (m_parentIsRule)
         visitor->trace(m_parentRule);
     else
         visitor->trace(m_parentStyleSheet);
 #endif
 }
 
 } // namespace blink