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

sync/tools/sync_client.cc

 // Copyright (c) 2012 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 <cstddef>
 #include <cstdio>
 #include <string>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
@@ skipping 104 matching lines @@
 
   bool DecryptString(const std::string& ciphertext,
                      std::string* plaintext) override {
     *plaintext = ciphertext;
     return true;
   }
 };
 
 std::string ValueToString(const base::Value& value) {
   std::string str;
-  base::JSONWriter::Write(&value, &str);
+  base::JSONWriter::Write(value, &str);
   return str;
 }
 
 class LoggingChangeDelegate : public SyncManager::ChangeDelegate {
  public:
   ~LoggingChangeDelegate() override {}
 
   void OnChangesApplied(ModelType model_type,
                         int64 model_version,
                         const BaseTransaction* trans,
@@ skipping 318 matching lines @@
   io_thread.Stop();
   return 0;
 }
 
 }  // namespace
 }  // namespace syncer
 
 int main(int argc, char* argv[]) {
   return syncer::SyncClientMain(argc, argv);
 }