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

third_party/WebKit/public/web/WebOptionElement.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 21 matching lines @@
 #define WebOptionElement_h
 
 #include "../platform/WebVector.h"
 #include "WebElement.h"
 
 namespace blink {
 
 class HTMLOptionElement;
 
 // Provides readonly access to some properties of a DOM option element node.
-class WebOptionElement : public WebElement {
+class WebOptionElement final : public WebElement {
 public:
     WebOptionElement() : WebElement() { }
     WebOptionElement(const WebOptionElement& element) : WebElement(element) { }
 
     WebOptionElement& operator=(const WebOptionElement& element)
     {
         WebElement::assign(element);
         return *this;
     }
     void assign(const WebOptionElement& element) { WebElement::assign(element); }
 
     BLINK_EXPORT void setValue(const WebString&);
     BLINK_EXPORT WebString value() const;
 
     BLINK_EXPORT int index() const;
     BLINK_EXPORT WebString text() const;
     BLINK_EXPORT WebString label() const;
     BLINK_EXPORT bool isEnabled() const;
 
 #if BLINK_IMPLEMENTATION
     WebOptionElement(const PassRefPtrWillBeRawPtr<HTMLOptionElement>&);
     WebOptionElement& operator=(const PassRefPtrWillBeRawPtr<HTMLOptionElement>&);
     operator PassRefPtrWillBeRawPtr<HTMLOptionElement>() const;
 #endif
 };
 
+DECLARE_WEB_NODE_TYPE_CASTS(WebOptionElement);
+
 } // namespace blink
 
 #endif