Add NGColumnLayoutAlgorithm skeleton implementation.

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

+// Copyright 2017 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 NGColumnLayoutAlgorithm_h
+#define NGColumnLayoutAlgorithm_h
+
+#include "core/layout/ng/ng_block_layout_algorithm.h"
+#include "core/layout/ng/ng_break_token.h"
+#include "core/layout/ng/ng_constraint_space.h"
+#include "core/layout/ng/ng_layout_result.h"
+#include "wtf/RefPtr.h"
+
+namespace blink {
+
+class NGBlockNode;
+
+class CORE_EXPORT NGColumnLayoutAlgorithm : public NGBlockLayoutAlgorithm {
+ public:
+  NGColumnLayoutAlgorithm(NGBlockNode* node,
+                          NGConstraintSpace* space,
+                          NGBreakToken* break_token = nullptr);
+
+  RefPtr<NGLayoutResult> Layout() override;
+};
+
+}  // namespace Blink
+
+#endif  // NGColumnLayoutAlgorithm_h