Add NGColumnLayoutAlgorithm skeleton implementation.

third_party/WebKit/Source/core/layout/ng/ng_block_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 NGBlockLayoutAlgorithm_h
 #define NGBlockLayoutAlgorithm_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/geometry/ng_margin_strut.h"
+#include "core/layout/ng/ng_block_break_token.h"
 #include "core/layout/ng/ng_block_node.h"
 #include "core/layout/ng/ng_constraint_space_builder.h"
 #include "core/layout/ng/ng_fragment_builder.h"
 #include "core/layout/ng/ng_layout_algorithm.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
-class ComputedStyle;
-class NGBlockBreakToken;
 class NGConstraintSpace;
 class NGLayoutResult;
 
 // A class for general block layout (e.g. a <div> with no special style).
 // Lays out the children in sequence.
-class CORE_EXPORT NGBlockLayoutAlgorithm : public NGLayoutAlgorithm {
+class CORE_EXPORT NGBlockLayoutAlgorithm
+    : public NGLayoutAlgorithm<NGBlockNode, NGBlockBreakToken> {
  public:
   // Default constructor.
   // @param node The input node to perform layout upon.
   // @param space The constraint space which the algorithm should generate a
   //              fragment within.
   // @param break_token The break token from which the layout should start.
   NGBlockLayoutAlgorithm(NGBlockNode* node,
                          NGConstraintSpace* space,
                          NGBlockBreakToken* break_token = nullptr);
 
   Optional<MinMaxContentSize> ComputeMinMaxContentSize() const override;
-  RefPtr<NGLayoutResult> Layout() override;
+  virtual RefPtr<NGLayoutResult> Layout() override;
 
  private:
   NGBoxStrut CalculateMargins(NGLayoutInputNode* child,
                               const NGConstraintSpace& space);
 
   // Creates a new constraint space for the current child.
   RefPtr<NGConstraintSpace> CreateConstraintSpaceForChild(NGLayoutInputNode*);
   void PrepareChildLayout(NGLayoutInputNode*);
   void FinishChildLayout(NGLayoutInputNode*,
                          NGConstraintSpace*,
                          RefPtr<NGLayoutResult>);
 
   // Final adjustments before fragment creation. We need to prevent the
   // fragment from crossing fragmentainer boundaries, and rather create a break
   // token if we're out of space.
   void FinalizeForFragmentation();
 
   // Calculates logical offset for the current fragment using either
   // {@code content_size_} when the fragment doesn't know it's offset
   // or {@code known_fragment_offset} if the fragment knows it's offset
   // @return Fragment's offset relative to the fragment's parent.
   NGLogicalOffset CalculateLogicalOffset(
       const WTF::Optional<NGLogicalOffset>& known_fragment_offset);
 
   // Updates the fragment's BFC offset if it's not already set.
   void UpdateFragmentBfcOffset(const NGLogicalOffset& offset);
 
-  const NGConstraintSpace& ConstraintSpace() const {
-    DCHECK(constraint_space_);
-    return *constraint_space_;
-  }
-
-  const ComputedStyle& Style() const { return node_->Style(); }
-
-  // Mutable Getters.
-  NGConstraintSpace* MutableConstraintSpace() { return constraint_space_; }
-
-  Persistent<NGBlockNode> node_;
-  NGConstraintSpace* constraint_space_;
-
-  // The break token from which we are currently resuming layout.
-  NGBlockBreakToken* break_token_;
-
   NGFragmentBuilder builder_;
   NGConstraintSpaceBuilder space_builder_;
 
   NGBoxStrut border_and_padding_;
   LayoutUnit content_size_;
   LayoutUnit max_inline_size_;
   // MarginStrut for the previous child.
   NGMarginStrut curr_margin_strut_;
   NGLogicalOffset curr_bfc_offset_;
   NGBoxStrut curr_child_margins_;
 };
 
 }  // namespace blink
 
 #endif  // NGBlockLayoutAlgorithm_h