Introduce a SVGUnknownElement class for unknown SVG elements

Source/core/dom/CustomElementRegistrationContext.cpp

Index: Source/core/dom/CustomElementRegistrationContext.cpp
diff --git a/Source/core/dom/CustomElementRegistrationContext.cpp b/Source/core/dom/CustomElementRegistrationContext.cpp
index 4e8129d6b10abe62def0cb06769e207209d62320..d37ba1eb465c887ccac85e468b4f5b1a08e2ebe2 100644
--- a/Source/core/dom/CustomElementRegistrationContext.cpp
+++ b/Source/core/dom/CustomElementRegistrationContext.cpp
@@ -39,7 +39,7 @@
 #include "core/dom/Element.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLUnknownElement.h"
-#include "core/svg/SVGElement.h"
+#include "core/svg/SVGUnknownElement.h"
 #include "wtf/RefPtr.h"
 
 namespace WebCore {
@@ -69,7 +69,7 @@ PassRefPtr<Element> CustomElementRegistrationContext::createCustomTagElement(Doc
     if (HTMLNames::xhtmlNamespaceURI == tagName.namespaceURI()) {
         element = HTMLElement::create(tagName, document);
     } else if (SVGNames::svgNamespaceURI == tagName.namespaceURI()) {
-        element = SVGElement::create(tagName, document);
+        element = SVGUnknownElement::create(tagName, document);
     } else {
         // XML elements are not custom elements, so return early.
         return Element::create(tagName, document);