Rewrite simple uses of base::ListValue::Append(base::Value*) on CrOS.

components/user_manager/known_user.cc

Index: components/user_manager/known_user.cc
diff --git a/components/user_manager/known_user.cc b/components/user_manager/known_user.cc
index 19fc5d97fd76f62098c94d85c2f93fa62becd5e2..8ad90614b9f3444673b46fb8a9fdb69ee8a2a7a8 100644
--- a/components/user_manager/known_user.cc
+++ b/components/user_manager/known_user.cc
@@ -7,6 +7,7 @@
 #include <stddef.h>
 
 #include <memory>
+#include <utility>
 
 #include "base/logging.h"
 #include "base/values.h"
@@ -137,7 +138,7 @@ void UpdatePrefs(const AccountId& account_id,
   std::unique_ptr<base::DictionaryValue> new_value(new base::DictionaryValue());
   new_value->MergeDictionary(&values);
   UpdateIdentity(account_id, *new_value);
-  update->Append(new_value.release());
+  update->Append(std::move(new_value));
 }
 
 bool GetStringPref(const AccountId& account_id,