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

chromeos/dbus/audio_node.h

 // Copyright (c) 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.
 
 #ifndef CHROMEOS_DBUS_AUDIO_NODE_H_
 #define CHROMEOS_DBUS_AUDIO_NODE_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 18 matching lines @@
 
   AudioNode();
   AudioNode(bool is_input,
             uint64_t id,
             uint64_t stable_device_id,
             std::string device_name,
             std::string type,
             std::string name,
             bool active,
             uint64_t plugged_time);
+  AudioNode(const AudioNode& other);
   ~AudioNode();
   std::string ToString() const;
 };
 
 typedef std::vector<AudioNode> AudioNodeList;
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_AUDIO_NODE_H_