diff --git a/tools/gn/visibility.cc b/tools/gn/visibility.cc
index 38d1b33..54d7280 100644
--- a/tools/gn/visibility.cc
+++ b/tools/gn/visibility.cc
@@ -88,7 +88,7 @@
   auto res = std::make_unique<base::ListValue>();
   for (const auto& pattern : patterns_)
     res->AppendString(pattern.Describe());
-  return res;
+  return std::move(res);
 }
 
 // static