Add ClearanceOffset to LayoutNG Constraint space.

third_party/WebKit/Source/core/layout/ng/ng_constraint_space_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 NGConstraintSpaceBuilder_h
 #define NGConstraintSpaceBuilder_h
 
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_units.h"
+#include "wtf/Optional.h"
 
 namespace blink {
 
 class CORE_EXPORT NGConstraintSpaceBuilder final
     : public GarbageCollectedFinalized<NGConstraintSpaceBuilder> {
  public:
   NGConstraintSpaceBuilder(const NGConstraintSpace* parent_space);
 
   NGConstraintSpaceBuilder(NGWritingMode writing_mode);
 
@@ skipping 19 matching lines @@
   NGConstraintSpaceBuilder& SetIsInlineDirectionTriggersScrollbar(
       bool is_inline_direction_triggers_scrollbar);
   NGConstraintSpaceBuilder& SetIsBlockDirectionTriggersScrollbar(
       bool is_block_direction_triggers_scrollbar);
 
   NGConstraintSpaceBuilder& SetFragmentationType(NGFragmentationType);
   NGConstraintSpaceBuilder& SetIsNewFormattingContext(bool is_new_fc);
 
   NGConstraintSpaceBuilder& SetMarginStrut(const NGMarginStrut& margin_strut);
 
-  NGConstraintSpaceBuilder& SetBfcOffset(const NGLogicalOffset& offset) {
-    bfc_offset_ = offset;
-    return *this;
-  }
+  NGConstraintSpaceBuilder& SetBfcOffset(const NGLogicalOffset& offset);
+
+  NGConstraintSpaceBuilder& SetClearanceOffset(
+      const WTF::Optional<LayoutUnit>& clearance_offset);
 
   // Creates a new constraint space. This may be called multiple times, for
   // example the constraint space will be different for a child which:
   //  - Establishes a new formatting context.
   //  - Is within a fragmentation container and needs its fragmentation offset
   //    updated.
   //  - Has its size is determined by its parent layout (flex, abs-pos).
   //
   // NGWritingMode specifies the writing mode of the generated space.
   NGConstraintSpace* ToConstraintSpace(NGWritingMode);
@@ skipping 14 matching lines @@
   unsigned is_shrink_to_fit_ : 1;
   unsigned is_inline_direction_triggers_scrollbar_ : 1;
   unsigned is_block_direction_triggers_scrollbar_ : 1;
   unsigned fragmentation_type_ : 2;
   unsigned is_new_fc_ : 1;
   unsigned text_direction_ : 1;
 
   NGMarginStrut margin_strut_;
   NGLogicalOffset bfc_offset_;
   std::shared_ptr<NGExclusions> exclusions_;
+  WTF::Optional<LayoutUnit> clearance_offset_;
 };
 
 }  // namespace blink
 
 #endif  // NGConstraintSpaceBuilder