Implementation of CSS3 nav-up/down/left/right properties from CSS3 UI.

Source/core/rendering/style/StyleNavigationValue.h

Index: Source/core/rendering/style/StyleNavigationValue.h
diff --git a/Source/core/rendering/style/StyleNavigationValue.h b/Source/core/rendering/style/StyleNavigationValue.h
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+/*
+ * Copyright (C) 2011 Kyounga Ra (kyounga.ra@gmail.com)
+ * Copyright (C) 2013 Opera Software ASA. 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 StyleNavigationValue_h
+#define StyleNavigationValue_h
+
+#include "wtf/text/WTFString.h"
+
+namespace WebCore {
+
+class StyleNavigationValue {
+public:
+    StyleNavigationValue()
+        : m_auto(true)
+        , m_id("")
+        , m_target("current")
+    { }
+
+    StyleNavigationValue(const AtomicString& id, const AtomicString& target = "current")
+        : m_auto(false)
+        , m_id(id)
+        , m_target(target)
+    { }
+
+    StyleNavigationValue(const String& id, const String& target = "current")
+        : m_auto(false)
+        , m_id(AtomicString(id))
+        , m_target(AtomicString(target))
+    { }
+
+    bool isAuto() const
+    {
+        return m_auto;
+    }
+
+    bool operator==(const StyleNavigationValue& o) const
+    {
+        if (m_auto)
+            return o.m_auto;
+        return m_id == o.m_id && m_target == o.m_target;
+    }
+
+    bool operator!=(const StyleNavigationValue& o) const
+    {
+        return !(*this == o);
+    }
+
+    void operator=(const StyleNavigationValue& o)
+    {
+        m_auto = o.m_auto;
+        m_id = o.m_id;
+        m_target = o.m_target;
+    }
+
+    const AtomicString& id() const { return m_id; }
+    const AtomicString& target() const { return m_target; }
+
+private:
+    bool m_auto;
+    AtomicString m_id;
+    AtomicString m_target;
+};
+
+} // namespace WebCore
+
+#endif // StyleNavigationValue_h