Remove raw base::DictionaryValue::Set in //extensions

extensions/browser/value_store/value_store_change.cc

Index: extensions/browser/value_store/value_store_change.cc
diff --git a/extensions/browser/value_store/value_store_change.cc b/extensions/browser/value_store/value_store_change.cc
index 023a2f371f477923d0687f4040b02a8c298dbddf..6f8517cf012131426d69bcab2d25b20ea12ad663 100644
--- a/extensions/browser/value_store/value_store_change.cc
+++ b/extensions/browser/value_store/value_store_change.cc
@@ -19,10 +19,12 @@ std::string ValueStoreChange::ToJson(
     std::unique_ptr<base::DictionaryValue> change_value =
         base::MakeUnique<base::DictionaryValue>();
     if (it->old_value()) {
-      change_value->Set("oldValue", it->old_value()->DeepCopy());
+      change_value->Set("oldValue",
+                        base::MakeUnique<base::Value>(*it->old_value()));
     }
     if (it->new_value()) {
-      change_value->Set("newValue", it->new_value()->DeepCopy());
+      change_value->Set("newValue",
+                        base::MakeUnique<base::Value>(*it->new_value()));
     }
     changes_value.SetWithoutPathExpansion(it->key(), std::move(change_value));
   }