Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderMultiColumnSet.h

 /*
  * Copyright (C) 2012 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 134 matching lines @@
 
     // The following variables are used when balancing the column set.
     LayoutUnit m_maxColumnHeight; // Maximum column height allowed.
     LayoutUnit m_minSpaceShortage; // The smallest amout of space shortage that caused a column break.
     LayoutUnit m_minimumColumnHeight;
     unsigned m_forcedBreaksCount; // FIXME: We will ultimately need to cache more information to balance around forced breaks properly.
     LayoutUnit m_maximumDistanceBetweenForcedBreaks;
     LayoutUnit m_forcedBreakOffset;
 };
 
-inline RenderMultiColumnSet* toRenderMultiColumnSet(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderMultiColumnSet());
-    return static_cast<RenderMultiColumnSet*>(object);
-}
-
-inline const RenderMultiColumnSet* toRenderMultiColumnSet(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderMultiColumnSet());
-    return static_cast<const RenderMultiColumnSet*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderMultiColumnSet(const RenderMultiColumnSet*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMultiColumnSet, isRenderMultiColumnSet());
 
 } // namespace WebCore
 
 #endif // RenderMultiColumnSet_h