Add RemoteDeviceLoader to create RemoteDevice from CryptAuth data.

components/proximity_auth/remote_device_life_cycle_impl_unittest.cc

Index: components/proximity_auth/remote_device_life_cycle_impl_unittest.cc
diff --git a/components/proximity_auth/remote_device_life_cycle_impl_unittest.cc b/components/proximity_auth/remote_device_life_cycle_impl_unittest.cc
index ade8caf2951f96c9b5efba070f0ad2a937c45a9c..77e3aa36959a414efa5c07a0988ac19cb0d83cde 100644
--- a/components/proximity_auth/remote_device_life_cycle_impl_unittest.cc
+++ b/components/proximity_auth/remote_device_life_cycle_impl_unittest.cc
@@ -28,6 +28,7 @@ namespace proximity_auth {
 namespace {
 
 // Attributes of the remote device under test.
+const char kRemoteDeviceUserId[] = "example@gmail.com";
 const char kRemoteDeviceName[] = "remote device";
 const char kRemoteDevicePublicKey[] = "public key";
 const char kRemoteDeviceBluetoothAddress[] = "AA:BB:CC:DD:EE:FF";
@@ -154,7 +155,8 @@ class ProximityAuthRemoteDeviceLifeCycleImplTest
       public RemoteDeviceLifeCycle::Observer {
  protected:
   ProximityAuthRemoteDeviceLifeCycleImplTest()
-      : life_cycle_(RemoteDevice(kRemoteDeviceName,
+      : life_cycle_(RemoteDevice(kRemoteDeviceUserId,
+                                 kRemoteDeviceName,
                                  kRemoteDevicePublicKey,
                                  kRemoteDeviceBluetoothAddress,
                                  kRemoteDevicePSK)),