Use unique pointers for U2fPacket and U2fMessage

device/u2f/u2f_message_fuzzer.cc

 // Copyright 2016 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 "net/base/io_buffer.h"
 #include "u2f_message.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   size_t packet_size = 65;
   size_t remaining_buffer = size;
   uint8_t* start = const_cast<uint8_t*>(data);
 
   scoped_refptr<net::IOBufferWithSize> buf(
       new net::IOBufferWithSize(packet_size));
   memcpy(buf->data(), start, std::min(packet_size, remaining_buffer));
-  scoped_refptr<device::U2fMessage> msg =
+  std::unique_ptr<device::U2fMessage> msg =
       device::U2fMessage::CreateFromSerializedData(buf);
 
   remaining_buffer -= std::min(remaining_buffer, packet_size);
   start += packet_size;
 
   while (remaining_buffer > 0) {
     size_t buffer_size = std::min(packet_size, remaining_buffer);
     scoped_refptr<net::IOBufferWithSize> tmp_buf(
         new net::IOBufferWithSize(buffer_size));
     memcpy(tmp_buf->data(), start, buffer_size);
     msg->AddContinuationPacket(tmp_buf);
     remaining_buffer -= std::min(remaining_buffer, buffer_size);
     start += buffer_size;
   }
 
   return 0;
 }