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

Source/bindings/templates/callback_interface.h

Index: Source/bindings/templates/callback_interface.h
diff --git a/Source/bindings/templates/callback_interface.h b/Source/bindings/templates/callback_interface.h
index 09679fe307eb0fa8510bb39e028812136db25fbc..a3ad2ec651aedcda9258ec12086d580c63d5996d 100644
--- a/Source/bindings/templates/callback_interface.h
+++ b/Source/bindings/templates/callback_interface.h
@@ -1,9 +1,4 @@
-// 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 {{v8_class}}_h
 #define {{v8_class}}_h