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

chromeos/network/network_configuration_handler.cc

Index: chromeos/network/network_configuration_handler.cc
diff --git a/chromeos/network/network_configuration_handler.cc b/chromeos/network/network_configuration_handler.cc
index d095e57ffc2b4980b8de625daa31eb6b9a3790ac..ac7ea8bcd1eaa1f90fcd6abd598f34ab9c6e8b2e 100644
--- a/chromeos/network/network_configuration_handler.cc
+++ b/chromeos/network/network_configuration_handler.cc
@@ -65,7 +65,7 @@ void LogConfigProperties(const std::string& desc,
        iter.Advance()) {
     std::string v = "******";
     if (shill_property_util::IsLoggableShillProperty(iter.key()))
-      base::JSONWriter::Write(&iter.value(), &v);
+      base::JSONWriter::Write(iter.value(), &v);
     NET_LOG(USER) << desc << ": " << path + "." + iter.key() + "=" + v;
   }
 }