[LayoutNG] PODify NGLayoutInputNode and sub-classes.

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

Index: third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.h
diff --git a/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.h b/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.h
index 81260737f705be3a3033d3f8f3dd0ee42e550701..171b0f4afe69b39e57ff1ef8d1e3aee9066449f2 100644
--- a/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.h
+++ b/third_party/WebKit/Source/core/layout/ng/layout_ng_block_flow.h
@@ -19,18 +19,17 @@ class CORE_EXPORT LayoutNGBlockFlow final : public LayoutBlockFlow {
   ~LayoutNGBlockFlow() override = default;
 
   void UpdateBlockLayout(bool relayout_children) override;
-  NGBlockNode* BoxForTesting() const { return box_.Get(); }
 
   const char* GetName() const override { return "LayoutNGBlockFlow"; }
 
   NGInlineNodeData& GetNGInlineNodeData() const;
   void ResetNGInlineNodeData();
+  bool HasNGInlineNodeData() const { return ng_inline_node_data_.get(); }
 
  private:
   bool IsOfType(LayoutObjectType) const override;
 
   std::unique_ptr<NGInlineNodeData> ng_inline_node_data_;
-  Persistent<NGBlockNode> box_;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutNGBlockFlow, IsLayoutNGBlockFlow());