[LayoutNG] Initial support for multicol, introducing NGBlockBreakToken.

third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.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 NGFragmentBuilder_h
 #define NGFragmentBuilder_h
 
 #include "core/layout/ng/ng_physical_fragment.h"
 #include "core/layout/ng/ng_units.h"
 
@@ skipping 63 matching lines @@
   //     builder->AddOutOfFlowDescendant();
   // }
   NGFragmentBuilder& AddOutOfFlowChildCandidate(NGBlockNode*, NGLogicalOffset);
 
   void GetAndClearOutOfFlowDescendantCandidates(WeakBoxList*,
                                                 Vector<NGStaticPosition>*);
 
   NGFragmentBuilder& AddOutOfFlowDescendant(NGBlockNode*,
                                             const NGStaticPosition&);
 
+  void SetBreakToken(NGBreakToken* token) {
+    DCHECK(!break_token_);
+    break_token_ = token;
+  }
+  bool HasBreakToken() const { return break_token_; }
+
   // Sets MarginStrut for the resultant fragment.
   NGFragmentBuilder& SetMarginStrutBlockStart(const NGMarginStrut& from);
   NGFragmentBuilder& SetMarginStrutBlockEnd(const NGMarginStrut& from);
 
   // Offsets are not supposed to be set during fragment construction, so we
   // do not provide a setter here.
 
   // Creates the fragment. Can only be called once.
   NGPhysicalBoxFragment* ToBoxFragment();
   NGPhysicalTextFragment* ToTextFragment(NGInlineNode*,
@@ skipping 31 matching lines @@
   NGMarginStrut margin_strut_;
 
   HeapVector<Member<NGPhysicalFragment>> children_;
   Vector<NGLogicalOffset> offsets_;
 
   WeakBoxList out_of_flow_descendant_candidates_;
   Vector<OutOfFlowPlacement> out_of_flow_candidate_placements_;
 
   WeakBoxList out_of_flow_descendants_;
   Vector<NGStaticPosition> out_of_flow_positions_;
+
+  Member<NGBreakToken> break_token_;
 };
 
 }  // namespace blink
 
 #endif  // NGFragmentBuilder