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

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

 /*
  * 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) 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 56 matching lines @@
   Attr(Document&, const QualifiedName&, const AtomicString& value);
 
   bool isElementNode() const =
       delete;  // This will catch anyone doing an unnecessary check.
 
   String nodeName() const override { return name(); }
   NodeType getNodeType() const override { return kAttributeNode; }
 
   String nodeValue() const override { return value(); }
   void setNodeValue(const String&) override;
-  Node* cloneNode(bool deep) override;
+  Node* cloneNode(bool deep, ExceptionState&) override;
 
   bool isAttributeNode() const override { return true; }
 
   // Attr wraps either an element/name, or a name/value pair (when it's a
   // standalone Node.)
   // Note that m_name is always set, but m_element/m_standaloneValue may be
   // null.
   TraceWrapperMember<Element> m_element;
   QualifiedName m_name;
   // Holds the value if it is a standalone Node, or the local name of the
   // attribute it is attached to on an Element. The latter may (letter case)
   // differ from m_name's local name. As these two modes are non-overlapping,
   // use a single field.
   AtomicString m_standaloneValueOrAttachedLocalName;
 };
 
 DEFINE_NODE_TYPE_CASTS(Attr, isAttributeNode());
 
 }  // namespace blink
 
 #endif  // Attr_h