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

third_party/WebKit/public/web/WebSelectElement.h

 /*
  * 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 22 matching lines @@
 
 #include "../platform/WebVector.h"
 #include "WebFormControlElement.h"
 #include "WebOptionElement.h"
 
 namespace blink {
 
 class HTMLSelectElement;
 
 // Provides readonly access to some properties of a DOM select element node.
-class WebSelectElement : public WebFormControlElement {
+class WebSelectElement final : public WebFormControlElement {
 public:
     WebSelectElement() : WebFormControlElement() { }
     WebSelectElement(const WebSelectElement& element) : WebFormControlElement(element) { }
 
     WebSelectElement& operator=(const WebSelectElement& element)
     {
         WebFormControlElement::assign(element);
         return *this;
     }
     void assign(const WebSelectElement& element) { WebFormControlElement::assign(element); }
 
     BLINK_EXPORT WebVector<WebElement> listItems() const;
 
 #if BLINK_IMPLEMENTATION
     WebSelectElement(const PassRefPtrWillBeRawPtr<HTMLSelectElement>&);
     WebSelectElement& operator=(const PassRefPtrWillBeRawPtr<HTMLSelectElement>&);
     operator PassRefPtrWillBeRawPtr<HTMLSelectElement>() const;
 #endif
 };
 
+DECLARE_WEB_NODE_TYPE_CASTS(WebSelectElement);
+
 } // namespace blink
 
 #endif