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

chromeos/system/statistics_provider.cc

Index: chromeos/system/statistics_provider.cc
diff --git a/chromeos/system/statistics_provider.cc b/chromeos/system/statistics_provider.cc
index d5b49d0bf8b8a4495a53e98f1a03063e1896b877..4c8bf1fd79eee539012bab7003c507afe75fe586 100644
--- a/chromeos/system/statistics_provider.cc
+++ b/chromeos/system/statistics_provider.cc
@@ -93,7 +93,7 @@ bool JoinListValuesToString(const base::DictionaryValue* dictionary,
 
   std::string buffer;
   bool first = true;
-  for (const base::Value* v : *list) {
+  for (const auto& v : *list) {
     std::string value;
     if (!v->GetAsString(&value))
       return false;