Remove unused V8 integration code in Sky

sky/engine/bindings/templates/callback_interface.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!
-
-#ifndef {{v8_class}}_h
-#define {{v8_class}}_h
-
-{% filter conditional(conditional_string) %}
-{% for filename in header_includes %}
-#include "{{filename}}"
-{% endfor %}
-
-namespace blink {
-
-class {{v8_class}} final : public {{cpp_class}}, public ActiveDOMCallback {
-public:
-    static PassOwnPtr<{{v8_class}}> create(v8::Handle<v8::Function> callback, ScriptState* scriptState)
-    {
-        return adoptPtr(new {{v8_class}}(callback, scriptState));
-    }
-
-    virtual ~{{v8_class}}();
-
-{% for method in methods %}
-    virtual {{method.cpp_type}} {{method.name}}({{method.argument_declarations | join(', ')}}) override;
-{% endfor %}
-private:
-    {{v8_class}}(v8::Handle<v8::Function>, ScriptState*);
-
-    ScopedPersistent<v8::Function> m_callback;
-    RefPtr<ScriptState> m_scriptState;
-};
-
-}
-{% endfilter %}
-#endif // {{v8_class}}_h