[LayoutNG] Add NGLayoutInputNode::ShowNodeTree

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

Index: third_party/WebKit/Source/core/layout/ng/ng_block_node.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_node.h b/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
index 511fe095ab7bf8320d7e9cf28c9c5dd6ab4cfe23..ed8518285539475290ee02e0619e85520658e5a0 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_node.h
@@ -34,7 +34,7 @@ class CORE_EXPORT NGBlockNode final : public NGLayoutInputNode {
   RefPtr<NGLayoutResult> Layout(NGConstraintSpace* constraint_space,
                                 NGBreakToken* break_token = nullptr) override;
   NGLayoutInputNode* NextSibling() override;
-  LayoutObject* GetLayoutObject() override;
+  LayoutObject* GetLayoutObject() const override;
 
   // Computes the value of min-content and max-content for this box.
   // If the underlying layout algorithm's ComputeMinMaxContentSize returns
@@ -63,6 +63,8 @@ class CORE_EXPORT NGBlockNode final : public NGLayoutInputNode {
 
   bool CanUseNewLayout();
 
+  String ToString() const override;
+
  private:
   // After we run the layout algorithm, this function copies back the geometry
   // data to the layout box.