[LayoutNG] Fix orthogonal writing mode child margin strut from being used in collapsing margins cal…

third_party/WebKit/Source/core/layout/ng/ng_fragment.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 NGFragment_h
 #define NGFragment_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_fragment_base.h"
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_physical_fragment.h"
 #include "core/layout/ng/ng_units.h"
 #include "core/layout/ng/ng_writing_mode.h"
 #include "platform/LayoutUnit.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class CORE_EXPORT NGFragment final : public NGFragmentBase {
  public:
   NGFragment(NGWritingMode writing_mode,
              NGDirection direction,
              NGPhysicalFragment* physical_fragment)
       : NGFragmentBase(writing_mode, direction, physical_fragment) {}
+
+  NGMarginStrut MarginStrut() const;
 };
 
 }  // namespace blink
 
 #endif  // NGFragment_h