Remove unnecessary override of Node#cloneNode in ShadowRoot's WebIDL

third_party/WebKit/Source/core/dom/Attr.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2012 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 77 matching lines @@
   else
     m_standaloneValueOrAttachedLocalName = value;
 }
 
 void Attr::setNodeValue(const String& v) {
   // Attr uses AtomicString type for its value to save memory as there
   // is duplication among Elements' attributes values.
   setValue(v.isNull() ? emptyAtom : AtomicString(v));
 }
 
-Node* Attr::cloneNode(bool /*deep*/) {
+Node* Attr::cloneNode(bool /*deep*/, ExceptionState&) {
   return new Attr(document(), m_name, value());
 }
 
 void Attr::detachFromElementWithValue(const AtomicString& value) {
   DCHECK(m_element);
   m_standaloneValueOrAttachedLocalName = value;
   m_element = nullptr;
 }
 
 void Attr::attachToElement(Element* element,
                            const AtomicString& attachedLocalName) {
   DCHECK(!m_element);
   m_element = element;
   m_standaloneValueOrAttachedLocalName = attachedLocalName;
 }
 
 DEFINE_TRACE(Attr) {
   visitor->trace(m_element);
   Node::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(Attr) {
   visitor->traceWrappers(m_element);
   Node::traceWrappers(visitor);
 }
 
 }  // namespace blink