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

extensions/browser/api/cast_channel/keep_alive_delegate.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <string>
 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "extensions/browser/api/cast_channel/cast_message_util.h"
 #include "extensions/browser/api/cast_channel/cast_socket.h"
@@ skipping 50 matching lines @@
 // static
 CastMessage KeepAliveDelegate::CreateKeepAliveMessage(
     const char* message_type) {
   CastMessage output;
   output.set_protocol_version(CastMessage::CASTV2_1_0);
   output.set_source_id(kPingSenderId);
   output.set_destination_id(kPingReceiverId);
   output.set_namespace_(kHeartbeatNamespace);
   base::DictionaryValue type_dict;
   type_dict.SetString(kTypeNodeId, message_type);
-  if (!base::JSONWriter::Write(&type_dict, output.mutable_payload_utf8())) {
+  if (!base::JSONWriter::Write(type_dict, output.mutable_payload_utf8())) {
     LOG(ERROR) << "Failed to serialize dictionary.";
     return output;
   }
   output.set_payload_type(
       CastMessage::PayloadType::CastMessage_PayloadType_STRING);
   return output;
 }
 
 KeepAliveDelegate::KeepAliveDelegate(
     CastSocket* socket,
@@ skipping 113 matching lines @@
   if (started_) {
     started_ = false;
     ping_timer_->Stop();
     liveness_timer_->Stop();
   }
 }
 
 }  // namespace cast_channel
 }  // namespace core_api
 }  // namespace extensions