Modify U2F apdu classes to use unique pointers

device/u2f/u2f_apdu_fuzzer.cc

 // Copyright 2017 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 <stddef.h>
 #include <stdint.h>
 #include <algorithm>
 
 #include "u2f_apdu_command.h"
 #include "u2f_apdu_response.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   std::vector<uint8_t> input(data, data + size);
-  scoped_refptr<device::U2fApduCommand> cmd =
+  std::unique_ptr<device::U2fApduCommand> cmd =
       device::U2fApduCommand::CreateFromMessage(input);
-  scoped_refptr<device::U2fApduResponse> rsp =
+  std::unique_ptr<device::U2fApduResponse> rsp =
       device::U2fApduResponse::CreateFromMessage(input);
   return 0;
 }