Add ClearanceOffset to LayoutNG Constraint space.

third_party/WebKit/Source/core/layout/ng/ng_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 NGConstraintSpace_h
 #define NGConstraintSpace_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_units.h"
 #include "core/layout/ng/ng_writing_mode.h"
@@ skipping 94 matching lines @@
 
   // Modifies constraint space to account for a placed fragment. Depending on
   // the shape of the fragment this will either modify the inline or block
   // size, or add an exclusion.
   void Subtract(const NGBoxFragment*);
 
   NGMarginStrut MarginStrut() const { return margin_strut_; }
 
   NGLogicalOffset BfcOffset() const { return bfc_offset_; }
 
+  WTF::Optional<LayoutUnit> ClearanceOffset() const {
+    return clearance_offset_;
+  }
+
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
   String ToString() const;
 
  private:
   friend class NGConstraintSpaceBuilder;
   // Default constructor.
   NGConstraintSpace(NGWritingMode,
                     TextDirection,
                     NGLogicalSize available_size,
                     NGLogicalSize percentage_resolution_size,
                     NGPhysicalSize initial_containing_block_size,
                     LayoutUnit fragmentainer_space_available,
                     bool is_fixed_size_inline,
                     bool is_fixed_size_block,
                     bool is_shrink_to_fit,
                     bool is_inline_direction_triggers_scrollbar,
                     bool is_block_direction_triggers_scrollbar,
                     NGFragmentationType block_direction_fragmentation_type,
                     bool is_new_fc,
                     const NGMarginStrut& margin_strut,
                     const NGLogicalOffset& bfc_offset,
-                    const std::shared_ptr<NGExclusions>& exclusions);
+                    const std::shared_ptr<NGExclusions>& exclusions,
+                    const WTF::Optional<LayoutUnit>& clearance_offset);
 
   NGPhysicalSize InitialContainingBlockSize() const {
     return initial_containing_block_size_;
   }
 
   NGLogicalSize available_size_;
   NGLogicalSize percentage_resolution_size_;
   NGPhysicalSize initial_containing_block_size_;
 
   LayoutUnit fragmentainer_space_available_;
@@ skipping 11 matching lines @@
   // Whether the current constraint space is for the newly established
   // formatting Context
   unsigned is_new_fc_ : 1;
 
   unsigned writing_mode_ : 3;
   unsigned direction_ : 1;
 
   NGMarginStrut margin_strut_;
   NGLogicalOffset bfc_offset_;
   const std::shared_ptr<NGExclusions> exclusions_;
+  WTF::Optional<LayoutUnit> clearance_offset_;
 };
 
 inline std::ostream& operator<<(std::ostream& stream,
                                 const NGConstraintSpace& value) {
   return stream << value.ToString();
 }
 
 }  // namespace blink
 
 #endif  // NGConstraintSpace_h