Cleanup: Start using toFoo methods as part of newly adopted coding guideline.

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
  * License as published by the Free Software Foundation; either
@@ skipping 85 matching lines @@
 {
     checkSetPrefix(prefix, es);
     if (es.hadException())
         return;
 
     if (prefix == xmlnsAtom && namespaceURI() != XMLNSNames::xmlnsNamespaceURI) {
         es.throwDOMException(NamespaceError, ExceptionMessages::failedToSet("prefix", "Attr", "The prefix '" + xmlnsAtom + "' may not be used on the namespace '" + namespaceURI() + "'."));
         return;
     }
 
-    if (static_cast<Attr*>(this)->qualifiedName() == xmlnsAtom) {
+    if (this->qualifiedName() == xmlnsAtom) {
         es.throwDOMException(NamespaceError, ExceptionMessages::failedToSet("prefix", "Attr", "The prefix '" + prefix + "' may not be used as a namespace prefix for attributes whose qualified name is '" + xmlnsAtom + "'."));
         return;
     }
 
     const AtomicString& newPrefix = prefix.isEmpty() ? nullAtom : prefix;
 
     if (m_element)
         elementAttribute().setPrefix(newPrefix);
     m_name.setPrefix(newPrefix);
 }
@@ skipping 96 matching lines @@
 }
 
 void Attr::attachToElement(Element* element)
 {
     ASSERT(!m_element);
     m_element = element;
     m_standaloneValue = nullAtom;
 }
 
 }