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

media/cast/test/simulator.cc

 // Copyright 2014 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.
 
 // Simulate end to end streaming.
 //
 // Input:
 // --source=
 //   WebM used as the source of video and audio frames.
 // --output=
@@ skipping 748 matching lines @@
   std::string sim_id = cmd->GetSwitchValueASCII(media::cast::kSimulationId);
 
   NetworkSimulationModel model = media::cast::LoadModel(
       cmd->GetSwitchValuePath(media::cast::kModelPath));
 
   base::DictionaryValue values;
   values.SetBoolean("sim", true);
   values.SetString("sim-id", sim_id);
 
   std::string extra_data;
-  base::JSONWriter::Write(&values, &extra_data);
+  base::JSONWriter::Write(values, &extra_data);
 
   // Run.
   media::cast::RunSimulation(source_path, log_output_path, metrics_output_path,
                              yuv_output_path, extra_data, model);
   return 0;
 }