Make NGFragment to own NGPhysicalFragment

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

Index: third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
index 524ac679dc2c58bfc2afd789fd7d5f2499738362..b73e45dc1a104517f9aa9a25df6cfbfa81493a49 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h
@@ -36,7 +36,7 @@ class CORE_EXPORT NGFragmentBuilder final
   // Creates the fragment. Can only be called once.
   NGPhysicalFragment* ToFragment();
 
-  DEFINE_INLINE_VIRTUAL_TRACE() { visitor->trace(children_); }
+  DEFINE_INLINE_VIRTUAL_TRACE(){};
 
  private:
   NGPhysicalFragmentBase::NGFragmentType type_;
@@ -48,7 +48,7 @@ class CORE_EXPORT NGFragmentBuilder final
 
   NGMarginStrut margin_strut_;
 
-  HeapVector<Member<NGPhysicalFragmentBase>> children_;
+  Vector<NGPhysicalFragmentBase*> children_;
   Vector<NGLogicalOffset> offsets_;
 };