[LayoutNG] A different approach to multi-col.

third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h

Index: third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
index 5bffa4f0f5b99bb6dcf791bd159c3ce0821a4753..1e04915a210a8a9d09d599425cc17b6f3b772e2c 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
@@ -19,7 +19,7 @@ class NGPhysicalTextFragment;
 
 class CORE_EXPORT NGFragmentBuilder final {
  public:
-  NGFragmentBuilder(NGPhysicalFragment::NGFragmentType, LayoutObject*);
+  NGFragmentBuilder(NGPhysicalFragment::NGFragmentType, NGLayoutInputNode*);
 
   using WeakBoxList = PersistentHeapLinkedHashSet<WeakMember<NGBlockNode>>;
 
@@ -35,6 +35,7 @@ class CORE_EXPORT NGFragmentBuilder final {
 
   NGFragmentBuilder& AddChild(RefPtr<NGPhysicalFragment>,
                               const NGLogicalOffset&);
+
   NGFragmentBuilder& AddFloatingObject(NGFloatingObject*,
                                        const NGLogicalOffset&);
 
@@ -75,11 +76,11 @@ class CORE_EXPORT NGFragmentBuilder final {
   NGFragmentBuilder& AddOutOfFlowDescendant(NGBlockNode*,
                                             const NGStaticPosition&);
 
-  void SetBreakToken(NGBreakToken* token) {
-    DCHECK(!break_token_);
-    break_token_ = token;
+  NGFragmentBuilder& SetUsedBlockSize(LayoutUnit used_block_size) {
+    used_block_size_ = used_block_size;
+    did_break_ = true;
+    return *this;
   }
-  bool HasBreakToken() const { return break_token_; }
 
   NGFragmentBuilder& SetEndMarginStrut(const NGMarginStrut& from) {
     end_margin_strut_ = from;
@@ -110,6 +111,8 @@ class CORE_EXPORT NGFragmentBuilder final {
     return bfc_offset_;
   }
 
+  bool DidBreak() const { return did_break_; }
+
  private:
   // Out-of-flow descendant placement information.
   // The generated fragment must compute NGStaticPosition for all
@@ -133,7 +136,7 @@ class CORE_EXPORT NGFragmentBuilder final {
   NGWritingMode writing_mode_;
   TextDirection direction_;
 
-  LayoutObject* layout_object_;
+  Persistent<NGLayoutInputNode> node_;
 
   NGLogicalSize size_;
   NGLogicalSize overflow_;
@@ -141,6 +144,11 @@ class CORE_EXPORT NGFragmentBuilder final {
   Vector<RefPtr<NGPhysicalFragment>> children_;
   Vector<NGLogicalOffset> offsets_;
 
+  bool did_break_;
+  LayoutUnit used_block_size_;
+
+  Persistent<HeapVector<Member<NGBreakToken>>> child_break_tokens_;
+
   WeakBoxList out_of_flow_descendant_candidates_;
   Vector<OutOfFlowPlacement> out_of_flow_candidate_placements_;
 
@@ -154,8 +162,6 @@ class CORE_EXPORT NGFragmentBuilder final {
   Vector<NGLogicalOffset> floating_object_offsets_;
   Vector<Persistent<NGFloatingObject>> positioned_floats_;
 
-  Persistent<NGBreakToken> break_token_;
-
   WTF::Optional<NGLogicalOffset> bfc_offset_;
   NGMarginStrut end_margin_strut_;
 };