[LayoutNG] A different approach to multi-col.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.cc b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.cc
index dfbad215933f77e5736b1095a01879700ee78459..e9a0484f1aaddb4f8b401d4c6e76957b11b61bc8 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.cc
@@ -4,21 +4,26 @@
 
 #include "core/layout/ng/ng_fragment_builder.h"
 
+#include "core/layout/ng/ng_block_break_token.h"
 #include "core/layout/ng/ng_block_node.h"
 #include "core/layout/ng/ng_break_token.h"
 #include "core/layout/ng/ng_fragment.h"
 #include "core/layout/ng/ng_physical_box_fragment.h"
 #include "core/layout/ng/ng_physical_text_fragment.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
 // TODO(ikilpatrick): Make writing mode and direction be in the constructor.
 NGFragmentBuilder::NGFragmentBuilder(NGPhysicalFragment::NGFragmentType type,
-                                     LayoutObject* layout_object)
+                                     NGLayoutInputNode* node)
     : type_(type),
       writing_mode_(kHorizontalTopBottom),
       direction_(TextDirection::kLtr),
-      layout_object_(layout_object) {}
+      node_(node),
+      did_break_(false) {
+  child_break_tokens_ = new HeapVector<Member<NGBreakToken>>();
+}
 
 NGFragmentBuilder& NGFragmentBuilder::SetWritingMode(
     NGWritingMode writing_mode) {
@@ -67,6 +72,13 @@ NGFragmentBuilder& NGFragmentBuilder::AddChild(
         OutOfFlowPlacement{child_offset, oof_position});
   }
 
+  DCHECK(child->BreakToken());
+  if (!child->BreakToken()->IsFinished()) {
+    // We have an unfinished child, we must produce an unfinished break token.
+    did_break_ = true;
+  }
+
+  child_break_tokens_->push_back(child->BreakToken());
   children_.push_back(std::move(child));
   offsets_.push_back(child_offset);
 
@@ -148,9 +160,6 @@ RefPtr<NGPhysicalBoxFragment> NGFragmentBuilder::ToBoxFragment() {
   DCHECK_EQ(type_, NGPhysicalFragment::kFragmentBox);
   DCHECK_EQ(offsets_.size(), children_.size());
 
-  auto* break_token = break_token_.get();
-  break_token_ = nullptr;
-
   NGPhysicalSize physical_size = size_.ConvertToPhysical(writing_mode_);
 
   for (size_t i = 0; i < children_.size(); ++i) {
@@ -162,6 +171,20 @@ RefPtr<NGPhysicalBoxFragment> NGFragmentBuilder::ToBoxFragment() {
   Vector<Persistent<NGFloatingObject>> positioned_floats;
   positioned_floats.reserveCapacity(positioned_floats_.size());
 
+  Persistent<NGBreakToken> break_token;
+  if (did_break_) {
+    break_token =
+        new NGBlockBreakToken(toNGBlockNode(node_.get()), LayoutUnit(0),
+                              used_block_size_, *child_break_tokens_.get());
+  } else {
+    if (node_->Type() == NGLayoutInputNode::kLegacyBlock) {
+      break_token = new NGBlockBreakToken(toNGBlockNode(node_.get()));
+    } else {
+      break_token =
+          new NGBreakToken(NGBreakToken::kTextBreakToken, true, node_);
+    }
+  }
+
   for (size_t i = 0; i < positioned_floats_.size(); ++i) {
     Persistent<NGFloatingObject>& floating_object = positioned_floats_[i];
     NGPhysicalFragment* floating_fragment = floating_object->fragment.get();
@@ -171,10 +194,10 @@ RefPtr<NGPhysicalBoxFragment> NGFragmentBuilder::ToBoxFragment() {
   }
 
   return adoptRef(new NGPhysicalBoxFragment(
-      layout_object_, physical_size, overflow_.ConvertToPhysical(writing_mode_),
-      children_, out_of_flow_descendants_, out_of_flow_positions_,
-      unpositioned_floats_, positioned_floats_, bfc_offset_, end_margin_strut_,
-      break_token));
+      node_->GetLayoutObject(), physical_size,
+      overflow_.ConvertToPhysical(writing_mode_), children_,
+      out_of_flow_descendants_, out_of_flow_positions_, unpositioned_floats_,
+      positioned_floats_, bfc_offset_, end_margin_strut_, break_token));
 }
 
 RefPtr<NGPhysicalTextFragment> NGFragmentBuilder::ToTextFragment(
@@ -189,12 +212,15 @@ RefPtr<NGPhysicalTextFragment> NGFragmentBuilder::ToTextFragment(
   Vector<Persistent<NGFloatingObject>> empty_unpositioned_floats;
   Vector<Persistent<NGFloatingObject>> empty_positioned_floats;
 
+  Persistent<NGBreakToken> break_token =
+      new NGBreakToken(NGBreakToken::kTextBreakToken, true, node_);
+
   return adoptRef(new NGPhysicalTextFragment(
-      layout_object_, node, index, start_offset, end_offset,
+      node_->GetLayoutObject(), node, index, start_offset, end_offset,
       size_.ConvertToPhysical(writing_mode_),
       overflow_.ConvertToPhysical(writing_mode_), out_of_flow_descendants_,
       out_of_flow_positions_, empty_unpositioned_floats,
-      empty_positioned_floats));
+      empty_positioned_floats, break_token));
 }
 
 }  // namespace blink