Add NGColumnLayoutAlgorithm skeleton implementation.

third_party/WebKit/Source/core/layout/ng/ng_layout_algorithm.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 NGLayoutAlgorithm_h
 #define NGLayoutAlgorithm_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_min_max_content_size.h"
 #include "wtf/Allocator.h"
-#include "wtf/Noncopyable.h"
 #include "wtf/Optional.h"
 
 namespace blink {
 
-struct MinMaxContentSize;
+class ComputedStyle;
+class NGConstraintSpace;
 class NGLayoutResult;
 
 // Base class for all LayoutNG algorithms.
+template <typename NGInputNodeType, typename NGBreakTokenType>
 class CORE_EXPORT NGLayoutAlgorithm {
   STACK_ALLOCATED();
+ public:
+  NGLayoutAlgorithm(NGInputNodeType* node,
+                    NGConstraintSpace* space,
+                    NGBreakTokenType* break_token)
+      : node_(node), constraint_space_(space), break_token_(break_token) {}
 
- public:
   virtual ~NGLayoutAlgorithm() {}
 
   // Actual layout function. Lays out the children and descendants within the
   // constraints given by the NGConstraintSpace. Returns a layout result with
   // the resulting layout information.
   // TODO(layout-dev): attempt to make this function const.
   virtual RefPtr<NGLayoutResult> Layout() = 0;
 
   // Computes the min-content and max-content intrinsic sizes for the given box.
   // The result will not take any min-width, max-width or width properties into
   // account. If the return value is empty, the caller is expected to synthesize
   // this value from the overflow rect returned from Layout called with an
   // available width of 0 and LayoutUnit::max(), respectively.
   virtual Optional<MinMaxContentSize> ComputeMinMaxContentSize() const {
     return WTF::nullopt;
   }
+
+ protected:
+  const NGConstraintSpace& ConstraintSpace() const {
+    DCHECK(constraint_space_);
+    return *constraint_space_;
+  }
+  NGConstraintSpace* MutableConstraintSpace() { return constraint_space_; }
+
+  const ComputedStyle& Style() const {
+    DCHECK(node_);
+    return node_->Style();
+  }
+
+  virtual NGInputNodeType* Node() const { return node_; }
+
+  NGBreakTokenType* BreakToken() const { return break_token_; }
+
+  Persistent<NGInputNodeType> node_;
+  NGConstraintSpace* constraint_space_;
+
+  // The break token from which we are currently resuming layout.
+  NGBreakTokenType* break_token_;
 };
 
 }  // namespace blink
 
 #endif  // NGLayoutAlgorithm_h