[LayoutNG] Initial NGLayoutOpportunityIterator implementation

third_party/WebKit/Source/core/layout/ng/ng_physical_constraint_space.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 NGPhysicalConstraintSpace_h
 #define NGPhysicalConstraintSpace_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_units.h"
 #include "platform/heap/Handle.h"
@@ skipping 29 matching lines @@
 class CORE_EXPORT NGPhysicalConstraintSpace final
     : public GarbageCollected<NGPhysicalConstraintSpace> {
  public:
   NGPhysicalConstraintSpace();
   NGPhysicalConstraintSpace(NGPhysicalSize);
   NGPhysicalConstraintSpace(const NGPhysicalConstraintSpace&);
 
   NGPhysicalSize ContainerSize() const { return container_size_; }
 
   void AddExclusion(const NGExclusion, unsigned options = 0);
-  DoublyLinkedList<const NGExclusion> Exclusions(unsigned options = 0) const;
+  const DoublyLinkedList<const NGExclusion>* Exclusions(
+      unsigned options = 0) const;
 
   DEFINE_INLINE_TRACE() {}
 
  private:
   friend class NGConstraintSpace;
 
   NGPhysicalSize container_size_;
 
   unsigned fixed_width_ : 1;
   unsigned fixed_height_ : 1;
   unsigned width_direction_triggers_scrollbar_ : 1;
   unsigned height_direction_triggers_scrollbar_ : 1;
   unsigned width_direction_fragmentation_type_ : 2;
   unsigned height_direction_fragmentation_type_ : 2;
 
   DoublyLinkedList<const NGExclusion> exclusions_;
 };
 
 }  // namespace blink
 
 #endif  // NGPhysicalConstraintSpace_h