Convert JsonWriter::Write to taking a const ref for the in-param

components/invalidation/invalidation_util.cc

Index: components/invalidation/invalidation_util.cc
diff --git a/components/invalidation/invalidation_util.cc b/components/invalidation/invalidation_util.cc
index 50e3a5c4908f39f63401b9379f8363f3e3b7b46e..d3706f48b73890b0878db9bce579e0e48886d78f 100644
--- a/components/invalidation/invalidation_util.cc
+++ b/components/invalidation/invalidation_util.cc
@@ -61,9 +61,8 @@ bool ObjectIdFromValue(const base::DictionaryValue& value,
 }
 
 std::string ObjectIdToString(const invalidation::ObjectId& object_id) {
-  scoped_ptr<base::DictionaryValue> value(ObjectIdToValue(object_id));
   std::string str;
-  base::JSONWriter::Write(value.get(), &str);
+  base::JSONWriter::Write(*ObjectIdToValue(object_id), &str);
   return str;
 }