Clean up toHTMLFooElement() using DEFINE_NODE_TYPE_CASTS_WITH_FUNCTION

Source/core/html/shadow/HTMLContentElement.h

Index: Source/core/html/shadow/HTMLContentElement.h
diff --git a/Source/core/html/shadow/HTMLContentElement.h b/Source/core/html/shadow/HTMLContentElement.h
index df52237d34fe7f1813653653cce7d949725e52ca..3b721b6cfb9db4c4c5bf806cb27905fc6674042c 100644
--- a/Source/core/html/shadow/HTMLContentElement.h
+++ b/Source/core/html/shadow/HTMLContentElement.h
@@ -101,11 +101,7 @@ inline bool isHTMLContentElement(const Element* element)
     return element->hasTagName(HTMLNames::contentTag);
 }
 
-inline HTMLContentElement* toHTMLContentElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || isHTMLContentElement(node));
-    return static_cast<HTMLContentElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(HTMLContentElement, hasTagName(HTMLNames::contentTag));
 
 }