WIP: redirect some LayoutBox methods to ng fragments

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..92f053ef72f3fd11b5d7078e364e44d01faf003c 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
@@ -170,11 +170,20 @@ RefPtr<NGPhysicalBoxFragment> NGFragmentBuilder::ToBoxFragment() {
     positioned_floats.push_back(floating_object);
   }
 
-  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));
+  RefPtr<NGPhysicalBoxFragment> final_box_fragment = 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));
+
+  if (layout_object_) {
+    // layout_object_ can be null in unit tests.
+    toLayoutBox(layout_object_)->setNGPhysicalFragment(final_box_fragment);
+  }
+
+  return final_box_fragment;
 }
 
 RefPtr<NGPhysicalTextFragment> NGFragmentBuilder::ToTextFragment(