components: Add out-of-line copy ctors for complex classes.

components/proximity_auth/remote_device.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_PROXIMITY_AUTH_REMOTE_DEVICE_H
 #define COMPONENTS_PROXIMITY_AUTH_REMOTE_DEVICE_H
 
 #include <string>
 #include <vector>
 
@@ skipping 12 matching lines @@
   std::string sign_in_challenge;
 
   RemoteDevice();
   RemoteDevice(const std::string& user_id,
                const std::string& name,
                const std::string& public_key,
                BluetoothType bluetooth_type,
                const std::string& bluetooth_address,
                const std::string& persistent_symmetric_key,
                std::string sign_in_challenge);
+  RemoteDevice(const RemoteDevice& other);
   ~RemoteDevice();
 };
 
 typedef std::vector<RemoteDevice> RemoteDeviceList;
 
 }  // namespace proximity_auth
 
 #endif  // COMPONENTS_PROXIMITY_AUTH_REMOTE_DEVICE_H