Remove unused V8 integration code in Sky

sky/engine/bindings/core/v8/Nullable.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.
-
-#ifndef SKY_ENGINE_BINDINGS_CORE_V8_NULLABLE_H_
-#define SKY_ENGINE_BINDINGS_CORE_V8_NULLABLE_H_
-
-#include "sky/engine/platform/heap/Handle.h"
-#include "sky/engine/wtf/Assertions.h"
-
-namespace blink {
-
-template <typename T>
-class Nullable {
-    DISALLOW_ALLOCATION();
-public:
-    Nullable()
-        : m_value()
-        , m_isNull(true) { }
-
-    Nullable(const T& value)
-        : m_value(value)
-        , m_isNull(false) { }
-
-    Nullable(const Nullable& other)
-        : m_value(other.m_value)
-        , m_isNull(other.m_isNull) { }
-
-    Nullable& operator=(const Nullable& other)
-    {
-        m_value = other.m_value;
-        m_isNull = other.m_isNull;
-        return *this;
-    }
-
-    void set(const T& value)
-    {
-        m_value = value;
-        m_isNull = false;
-    }
-    const T& get() const { ASSERT(!m_isNull); return m_value; }
-    T& get() { ASSERT(!m_isNull); return m_value; }
-    bool isNull() const { return m_isNull; }
-
-    // See comment in RefPtr.h about what UnspecifiedBoolType is.
-    typedef const T* UnspecifiedBoolType;
-    operator UnspecifiedBoolType() const { return m_isNull ? 0 : &m_value; }
-
-    bool operator==(const Nullable& other) const
-    {
-        return (m_isNull && other.m_isNull) || (!m_isNull && !other.m_isNull && m_value == other.m_value);
-    }
-
-private:
-    T m_value;
-    bool m_isNull;
-};
-
-} // namespace blink
-
-#endif  // SKY_ENGINE_BINDINGS_CORE_V8_NULLABLE_H_