Convert //remoting to use std::unique_ptr

remoting/host/pairing_registry_delegate_mac.cc

 // Copyright 2013 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 "remoting/host/pairing_registry_delegate.h"
 
 #include "base/task_runner.h"
 
 namespace remoting {
 
 using protocol::PairingRegistry;
 
-scoped_ptr<PairingRegistry::Delegate> CreatePairingRegistryDelegate() {
+std::unique_ptr<PairingRegistry::Delegate> CreatePairingRegistryDelegate() {
   return nullptr;
 }
 
 }  // namespace remoting