[LayoutNG] Initial support for multicol, introducing NGBlockBreakToken.

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 52 matching lines @@
 
   // The available space size.
   // See: https://drafts.csswg.org/css-sizing/#available
   NGLogicalSize AvailableSize() const { return available_size_; }
 
   // Offset relative to the root constraint space.
   NGLogicalOffset Offset() const { return offset_; }
   // TODO(layout-ng): Set offset via NGConstraintSpacebuilder.
   void SetOffset(const NGLogicalOffset& offset) { offset_ = offset; }
 
+  // Return the block-direction space available in the current fragmentainer.
+  LayoutUnit FragmentainerSpaceAvailable() const {
+    DCHECK(HasBlockFragmentation());
+    return fragmentainer_space_available_;
+  }
+
   // Whether the current constraint space is for the newly established
   // Formatting Context.
   bool IsNewFormattingContext() const { return is_new_fc_; }
 
   // Whether exceeding the AvailableSize() triggers the presence of a scrollbar
   // for the indicated direction.
   // If exceeded the current layout should be aborted and invoked again with a
   // constraint space modified to reserve space for a scrollbar.
   bool IsInlineDirectionTriggersScrollbar() const {
     return is_inline_direction_triggers_scrollbar_;
@@ skipping 14 matching lines @@
   bool IsFixedSizeBlock() const { return is_fixed_size_block_; }
 
   // Whether an auto inline-size should be interpreted as shrink-to-fit
   // (ie. fit-content). This is used for inline-block, floats, etc.
   bool IsShrinkToFit() const { return is_shrink_to_fit_; }
 
   // If specified a layout should produce a Fragment which fragments at the
   // blockSize if possible.
   NGFragmentationType BlockFragmentationType() const;
 
+  // Return true if this contraint space participates in a fragmentation
+  // context.
+  bool HasBlockFragmentation() const {
+    return BlockFragmentationType() != kFragmentNone;
+  }
+
   // 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*);
 
   NGLayoutOpportunityIterator* LayoutOpportunities(
       unsigned clear = kNGClearNone,
       bool for_inline_or_bfc = false);
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
   String ToString() const;
 
  private:
   friend class NGConstraintSpaceBuilder;
   // Default constructor.
   NGConstraintSpace(NGWritingMode,
                     TextDirection,
                     NGLogicalSize available_size,
                     NGLogicalSize percentage_resolution_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 std::shared_ptr<NGExclusions>& exclusions_);
 
   NGLogicalSize available_size_;
   NGLogicalSize percentage_resolution_size_;
 
+  LayoutUnit fragmentainer_space_available_;
+
   unsigned is_fixed_size_inline_ : 1;
   unsigned is_fixed_size_block_ : 1;
 
   unsigned is_shrink_to_fit_ : 1;
 
   unsigned is_inline_direction_triggers_scrollbar_ : 1;
   unsigned is_block_direction_triggers_scrollbar_ : 1;
 
   unsigned block_direction_fragmentation_type_ : 2;
 
   // Whether the current constraint space is for the newly established
   // formatting Context
   unsigned is_new_fc_ : 1;
 
   NGLogicalOffset offset_;
   unsigned writing_mode_ : 3;
   unsigned direction_ : 1;
 
   const std::shared_ptr<NGExclusions> exclusions_;
 };
 
 inline std::ostream& operator<<(std::ostream& stream,
                                 const NGConstraintSpace& value) {
   return stream << value.ToString();
 }
 
 }  // namespace blink
 
 #endif  // NGConstraintSpace_h