Replace static_cast<Element*> with toElement

Source/core/dom/Element.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, 2010, 2011, 2013 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 753 matching lines @@
 {
     ContainerNode* parent = parentNode();
     return parent && parent->isElementNode() ? toElement(parent) : 0;
 }
 
 inline Element* Node::previousElementSibling() const
 {
     Node* n = previousSibling();
     while (n && !n->isElementNode())
         n = n->previousSibling();
-    return static_cast<Element*>(n);
+    return toElement(n);
 }
 
 inline Element* Node::nextElementSibling() const
 {
     Node* n = nextSibling();
     while (n && !n->isElementNode())
         n = n->nextSibling();
-    return static_cast<Element*>(n);
+    return toElement(n);
 }
 
 inline bool Element::fastHasAttribute(const QualifiedName& name) const
 {
     ASSERT(fastAttributeLookupAllowed(name));
     return elementData() && getAttributeItem(name);
 }
 
 inline const AtomicString& Element::fastGetAttribute(const QualifiedName& name) const
 {
@@ skipping 202 matching lines @@
 
 inline const Attribute* ElementData::attributeItem(unsigned index) const
 {
     RELEASE_ASSERT(index < length());
     return attributeBase() + index;
 }
 
 } // namespace
 
 #endif