[LayoutNG] Initial support for multicol, introducing NGBlockBreakToken.

third_party/WebKit/Source/core/layout/ng/ng_block_node.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 NGBlockNode_h
 #define NGBlockNode_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_layout_input_node.h"
+#include "core/layout/ng/ng_physical_box_fragment.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class ComputedStyle;
 class LayoutBox;
 class LayoutObject;
+class NGBreakToken;
 class NGConstraintSpace;
 class NGFragment;
 class NGLayoutAlgorithm;
 class NGLayoutCoordinator;
-class NGPhysicalBoxFragment;
 struct MinAndMaxContentSizes;
 
 // Represents a node to be laid out.
 class CORE_EXPORT NGBlockNode final : public NGLayoutInputNode {
   friend NGLayoutInputNode;
 
  public:
   explicit NGBlockNode(LayoutObject*);
 
   // TODO(layout-ng): make it private and declare a friend class to use in tests
@@ skipping 16 matching lines @@
   bool ComputeMinAndMaxContentSizes(MinAndMaxContentSizes*);
 
   const ComputedStyle* Style() const;
   ComputedStyle* MutableStyle();
 
   NGLayoutInputNode* FirstChild();
 
   void SetNextSibling(NGBlockNode*);
   void SetFirstChild(NGLayoutInputNode*);
 
+  void SetFragment(NGPhysicalBoxFragment* fragment) { fragment_ = fragment; }
+  NGBreakToken* CurrentBreakToken() const;
+  bool IsLayoutFinished() const {
+    return fragment_ && !fragment_->BreakToken();
+  }
+
   DECLARE_VIRTUAL_TRACE();
 
   // Runs layout on layout_box_ and creates a fragment for the resulting
   // geometry.
   NGPhysicalBoxFragment* RunOldLayout(const NGConstraintSpace&);
 
   // Called if this is an out-of-flow block which needs to be
   // positioned with legacy layout.
   void UseOldOutOfFlowPositioning();
 
@@ skipping 14 matching lines @@
   void CopyFragmentDataToLayoutBox(const NGConstraintSpace&);
 
   // We can either wrap a layout_box_ or a style_/next_sibling_/first_child_
   // combination.
   LayoutBox* layout_box_;
   RefPtr<ComputedStyle> style_;
   Member<NGBlockNode> next_sibling_;
   Member<NGLayoutInputNode> first_child_;
   Member<NGLayoutCoordinator> layout_coordinator_;
   Member<NGLayoutAlgorithm> minmax_algorithm_;
+  // TODO(mstensho): An input node may produce multiple fragments, so this
+  // should probably be renamed to last_fragment_ or something like that, since
+  // the last fragment is all we care about when resuming layout.
   Member<NGPhysicalBoxFragment> fragment_;
 };
 
 DEFINE_TYPE_CASTS(NGBlockNode,
                   NGLayoutInputNode,
                   node,
                   node->Type() == NGLayoutInputNode::kLegacyBlock,
                   node.Type() == NGLayoutInputNode::kLegacyBlock);
 
 }  // namespace blink
 
 #endif  // NGBlockNode