Move core/layout/style to core/style

Source/core/layout/style/DataRef.h

-/*
- * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
- *           (C) 2000 Antti Koivisto (koivisto@kde.org)
- *           (C) 2000 Dirk Mueller (mueller@kde.org)
- * Copyright (C) 2003, 2005, 2008 Apple Inc. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- *
- */
-
-#ifndef DataRef_h
-#define DataRef_h
-
-#include "wtf/RefPtr.h"
-
-namespace blink {
-
-template <typename T> class DataRef {
-public:
-    const T* get() const { return m_data.get(); }
-
-    const T& operator*() const { return *get(); }
-    const T* operator->() const { return get(); }
-
-    T* access()
-    {
-        if (!m_data->hasOneRef())
-            m_data = m_data->copy();
-        return m_data.get();
-    }
-
-    void init()
-    {
-        ASSERT(!m_data);
-        m_data = T::create();
-    }
-
-    bool operator==(const DataRef<T>& o) const
-    {
-        ASSERT(m_data);
-        ASSERT(o.m_data);
-        return m_data == o.m_data || *m_data == *o.m_data;
-    }
-
-    bool operator!=(const DataRef<T>& o) const
-    {
-        ASSERT(m_data);
-        ASSERT(o.m_data);
-        return m_data != o.m_data && *m_data != *o.m_data;
-    }
-
-    void operator=(std::nullptr_t) { m_data = nullptr; }
-private:
-    RefPtr<T> m_data;
-};
-
-} // namespace blink
-
-#endif // DataRef_h