Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderMultiColumnSet.h

Index: Source/core/rendering/RenderMultiColumnSet.h
diff --git a/Source/core/rendering/RenderMultiColumnSet.h b/Source/core/rendering/RenderMultiColumnSet.h
index d60bd977608a087fb42e7b4f04e05a394058b97e..3ebfc5e9c561abfdaa9527816396db266ccaa098 100644
--- a/Source/core/rendering/RenderMultiColumnSet.h
+++ b/Source/core/rendering/RenderMultiColumnSet.h
@@ -152,20 +152,7 @@ private:
     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