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

Source/bindings/templates/dictionary_impl.cpp

-// 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' %}
 #include "config.h"
 #include "{{cpp_class}}.h"
 
 {% for filename in cpp_includes %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace blink {
 
 {# Constructor #}
 {{cpp_class}}::{{cpp_class}}()
 {
     {% for member in members if member.cpp_default_value %}
     {{member.setter_name}}({{member.cpp_default_value}});
     {% endfor %}
 }
 
 DEFINE_TRACE({{cpp_class}})
 {
     {% for member in members if member.is_traceable %}
     visitor->trace(m_{{member.cpp_name}});
     {% endfor %}
     {% if parent_cpp_class %}
     {{parent_cpp_class}}::trace(visitor);
     {% endif %}
 }
 
 } // namespace blink