Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGElement.h

Index: Source/core/svg/SVGElement.h
diff --git a/Source/core/svg/SVGElement.h b/Source/core/svg/SVGElement.h
index 83b01604ba901cd2c82abf62559068ab7953575e..5dd3f1635a3b68cabb9125d6bad7b6fe8ba032b4 100644
--- a/Source/core/svg/SVGElement.h
+++ b/Source/core/svg/SVGElement.h
@@ -207,17 +207,7 @@ struct SVGAttributeHashTranslator {
     static bool equal(const QualifiedName& a, const QualifiedName& b) { return a.matches(b); }
 };
 
-inline SVGElement* toSVGElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isSVGElement());
-    return static_cast<SVGElement*>(node);
-}
-
-inline const SVGElement* toSVGElement(const Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isSVGElement());
-    return static_cast<const SVGElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGElement, isSVGElement());
 
 }