diff --git a/components/prefs/pref_service_unittest.cc b/components/prefs/pref_service_unittest.cc
index ea9577726..373c01b 100644
--- a/components/prefs/pref_service_unittest.cc
+++ b/components/prefs/pref_service_unittest.cc
@@ -414,7 +414,7 @@
   Mock::VerifyAndClearExpectations(&observer_);
 
   base::ListValue new_value;
-  new_value.Append(new base::StringValue(kValue));
+  new_value.AppendString(kValue);
   observer_.Expect(kName, &new_value);
   prefs_.Set(kName, new_value);
   Mock::VerifyAndClearExpectations(&observer_);