Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/svg/RenderSVGRoot.h

Index: Source/core/rendering/svg/RenderSVGRoot.h
diff --git a/Source/core/rendering/svg/RenderSVGRoot.h b/Source/core/rendering/svg/RenderSVGRoot.h
index 2d1a1d2aaa16d0dafb0a306e49dc03dcdea5fd40..e1e0664fce5d756c635d5b3361e450aeda1a1d92 100644
--- a/Source/core/rendering/svg/RenderSVGRoot.h
+++ b/Source/core/rendering/svg/RenderSVGRoot.h
@@ -119,20 +119,7 @@ private:
     bool m_needsBoundariesOrTransformUpdate : 1;
 };
 
-inline RenderSVGRoot* toRenderSVGRoot(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isSVGRoot());
-    return static_cast<RenderSVGRoot*>(object);
-}
-
-inline const RenderSVGRoot* toRenderSVGRoot(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isSVGRoot());
-    return static_cast<const RenderSVGRoot*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderSVGRoot(const RenderSVGRoot*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGRoot, isSVGRoot());
 
 } // namespace WebCore