Make WebNode::to<Type>() (and toConst) casts contain type asserts.

third_party/WebKit/Source/web/WebSelectElement.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 36 matching lines @@
         items[i] = WebElement(sourceItems[i].get());
 
     return items;
 }
 
 WebSelectElement::WebSelectElement(const PassRefPtrWillBeRawPtr<HTMLSelectElement>& element)
     : WebFormControlElement(element)
 {
 }
 
+DEFINE_WEB_NODE_TYPE_CASTS(WebSelectElement, isHTMLSelectElement(constUnwrap<Node>()));
+
 WebSelectElement& WebSelectElement::operator=(const PassRefPtrWillBeRawPtr<HTMLSelectElement>& element)
 {
     m_private = element;
     return *this;
 }
 
 WebSelectElement::operator PassRefPtrWillBeRawPtr<HTMLSelectElement>() const
 {
     return toHTMLSelectElement(m_private.get());
 }
 
 } // namespace blink