Count element name validity per DOM versus HTML parsing.

third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CustomElementTestHelpers_h
 #define CustomElementTestHelpers_h
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
@@ skipping 105 matching lines @@
   CreateElement& WithIsAttribute(const AtomicString& value) {
     attributes_.push_back(std::make_pair(HTMLNames::isAttr, value));
     return *this;
   }
 
   operator Element*() const {
     Document* document = document_.Get();
     if (!document)
       document = HTMLDocument::Create();
     NonThrowableExceptionState no_exceptions;
-    Element* element =
-        document->createElementNS(namespace_uri_, local_name_, no_exceptions);
+    Element* element = document->createElementNS(nullptr, namespace_uri_,
+                                                 local_name_, no_exceptions);
     for (const auto& attribute : attributes_)
       element->setAttribute(attribute.first, attribute.second);
     return element;
   }
 
  private:
   Member<Document> document_;
   AtomicString namespace_uri_;
   AtomicString local_name_;
   std::vector<std::pair<QualifiedName, AtomicString>> attributes_;
 };
 
 }  // namespace blink
 
 #endif  // CustomElementTestHelpers_h