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

remoting/client/plugin/chromoting_instance.cc

Index: remoting/client/plugin/chromoting_instance.cc
diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index 3faab96508cb0a30d58ea19e0c8a17d3bba03919..a3544aa9fcbbbd5c0942a44d58875e7a3ca13983 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -1016,12 +1016,12 @@ void ChromotingInstance::PostChromotingMessage(const std::string& method,
 void ChromotingInstance::PostLegacyJsonMessage(
     const std::string& method,
     scoped_ptr<base::DictionaryValue> data) {
-  scoped_ptr<base::DictionaryValue> message(new base::DictionaryValue());
-  message->SetString("method", method);
-  message->Set("data", data.release());
+  base::DictionaryValue message;
+  message.SetString("method", method);
+  message.Set("data", data.release());
 
   std::string message_json;
-  base::JSONWriter::Write(message.get(), &message_json);
+  base::JSONWriter::Write(message, &message_json);
   PostMessage(pp::Var(message_json));
 }