Add RemoteDeviceLoader to create RemoteDevice from CryptAuth data.

components/proximity_auth/remote_device.cc

 // Copyright 2015 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 "components/proximity_auth/remote_device.h"
 
 namespace proximity_auth {
 
 RemoteDevice::RemoteDevice() {}
 
-RemoteDevice::RemoteDevice(const std::string& name,
+RemoteDevice::RemoteDevice(const std::string& user_id,
+                           const std::string& name,
                            const std::string& public_key,
                            const std::string& bluetooth_address,
                            const std::string& persistent_symmetric_key)
-    : name(name),
+    : user_id(user_id),
+      name(name),
       public_key(public_key),
       bluetooth_address(bluetooth_address),
       persistent_symmetric_key(persistent_symmetric_key) {}
 
 RemoteDevice::~RemoteDevice() {}
 
 }  // namespace