[LayoutNG] Initial version of NGBox wrapper object.

third_party/WebKit/Source/core/layout/ng/ng_box.h

+// Copyright 2016 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 NGBox_h
+#define NGBox_h
+
+#include "core/CoreExport.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class ComputedStyle;
+class LayoutObject;
+class NGConstraintSpace;
+class NGFragment;
+
+// Represents a node to be laid out.
+class CORE_EXPORT NGBox final {
+ public:
+  explicit NGBox(const LayoutObject* layoutObject)
+      : m_layoutObject(layoutObject) {}
+
+  operator bool() const { return m_layoutObject; }
+
+  NGFragment* layout(const NGConstraintSpace&);
+  const ComputedStyle* style() const;
+
+  // TODO(layout-ng): Returning a children iterator would be better here.
+  const NGBox firstChild() const;
+  const NGBox nextSibling() const;
+
+ private:
+  const LayoutObject* m_layoutObject;
+};
+
+}  // namespace blink
+
+#endif  // NGBox_h