Use std::unique_ptr for base::DictionaryValue and base::ListValue's internal store.

components/signin/core/browser/account_tracker_service.cc

Index: components/signin/core/browser/account_tracker_service.cc
diff --git a/components/signin/core/browser/account_tracker_service.cc b/components/signin/core/browser/account_tracker_service.cc
index 12965902a881cfc659eb94afb6895bbca2b857e4..b1dc370db2b727dddebcc37796f50de2687905b8 100644
--- a/components/signin/core/browser/account_tracker_service.cc
+++ b/components/signin/core/browser/account_tracker_service.cc
@@ -348,7 +348,7 @@ void AccountTrackerService::LoadFromPrefs() {
         if (dict->GetList(kAccountServiceFlagsPath, &service_flags_list)) {
           contains_deprecated_service_flags = true;
           std::string flag_string;
-          for (base::Value* flag : *service_flags_list) {
+          for (const auto& flag : *service_flags_list) {
             if (flag->GetAsString(&flag_string) &&
                 flag_string == kChildAccountServiceFlag) {
               is_child_account = true;