[LayoutNG] Switch NGBreakToken to being RefCounted.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
index a755d5ac107dacdcbe1c428a14e894e3a1971784..dcbed4f792bd10c94ea5e01918bdb3d132f9eada 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
@@ -306,10 +306,10 @@ bool IsOutOfSpace(const NGConstraintSpace& space, LayoutUnit content_size) {
 NGBlockLayoutAlgorithm::NGBlockLayoutAlgorithm(
     NGBlockNode* node,
     NGConstraintSpace* constraint_space,
-    NGBlockBreakToken* break_token)
+    RefPtr<NGBlockBreakToken> break_token)
     : node_(node),
       constraint_space_(constraint_space),
-      break_token_(break_token),
+      break_token_(std::move(break_token)),
       builder_(WTF::wrapUnique(
           new NGFragmentBuilder(NGPhysicalFragment::kFragmentBox, node))) {}
 
@@ -411,7 +411,7 @@ RefPtr<NGLayoutResult> NGBlockLayoutAlgorithm::Layout() {
   builder_->SetWritingMode(constraint_space_->WritingMode());
   builder_->SetInlineSize(inline_size).SetBlockSize(block_size);
 
-  NGBlockChildIterator child_iterator(node_->FirstChild(), break_token_);
+  NGBlockChildIterator child_iterator(node_->FirstChild(), break_token_.get());
   NGBlockChildIterator::Entry entry = child_iterator.NextChild();
   current_child_ = entry.node;
   NGBreakToken* child_break_token = entry.token;