Make generated Callback bindings classes FINAL

Source/bindings/templates/callback_interface.h

 {# http://www.chromium.org/blink/coding-style#TOC-License #}
 /*
  * Copyright (C) 2013 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.
@@ skipping 26 matching lines @@
 
 {% filter conditional(conditional_string) %}
 {% for filename in header_includes %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace WebCore {
 
 class ExecutionContext;
 
-class {{v8_class}} : public {{cpp_class}}, public ActiveDOMCallback {
+class {{v8_class}} FINAL : public {{cpp_class}}, public ActiveDOMCallback {
 public:
     static PassOwnPtr<{{v8_class}}> create(v8::Handle<v8::Function> callback, ExecutionContext* context)
     {
         ASSERT(context);
         return adoptPtr(new {{v8_class}}(callback, context));
     }
 
     virtual ~{{v8_class}}();
 
 {% for method in methods %}
-    virtual {{method.return_cpp_type}} {{method.name}}({{method.argument_declarations | join(', ')}});
+    virtual {{method.return_cpp_type}} {{method.name}}({{method.argument_declarations | join(', ')}}) OVERRIDE;
 {% endfor %}
 private:
     {{v8_class}}(v8::Handle<v8::Function>, ExecutionContext*);
 
     ScopedPersistent<v8::Function> m_callback;
     RefPtr<DOMWrapperWorld> m_world;
 };
 
 }
 {% endfilter %}
 #endif // {{v8_class}}_h