[LayoutNG] Introduce NGPhysicalFragment and make NGFragment a 'view'

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"
 #include "wtf/DoublyLinkedList.h"
 
 namespace blink {
 
 enum NGExclusionType {
   NGClearNone = 0,
   NGClearFloatLeft = 1,
   NGClearFloatRight = 2,
   NGClearFragment = 4
 };
 
 enum NGFragmentationType {
   FragmentNone,
   FragmentPage,
   FragmentColumn,
   FragmentRegion
 };
 
-enum NGDirection { LeftToRight = 0, RightToLeft = 1 };
-
 class NGExclusion {
  public:
   NGExclusion();
   ~NGExclusion() {}
 };
 
 // The NGPhysicalConstraintSpace contains the underlying data for the
 // NGConstraintSpace. It is not meant to be used directly as all members are in
 // the physical coordinate space. Instead NGConstraintSpace should be used.
 class CORE_EXPORT NGPhysicalConstraintSpace final
@@ skipping 22 matching lines @@
   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