[bindings] Include copyright block in generated code for consistency.

Source/bindings/templates/dictionary_impl.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This file has been auto-generated by {{code_generator}}. DO NOT MODIFY!
-
+{% include 'copyright_block.txt' %}
 #ifndef {{cpp_class}}_h
 #define {{cpp_class}}_h
 
 {% for filename in header_includes %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace blink {
 
 {# FIXME: Add "final" if this class doesn't have subclasses #}
@@ skipping 17 matching lines @@
     {% for member in members %}
     {{member.member_cpp_type}} m_{{member.cpp_name}};
     {% endfor %}
 
     friend class V8{{cpp_class}};
 };
 
 } // namespace blink
 
 #endif // {{cpp_class}}_h