Replace more ObserverList with base::ObserverList.

device/nfc/nfc_tag_chromeos.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 DEVICE_NFC_NFC_TAG_CHROMEOS_H_
 #define DEVICE_NFC_NFC_TAG_CHROMEOS_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 41 matching lines @@
   dbus::ObjectPath object_path_;
 
   // Stores whether or not the initial set of properties have been received.
   bool is_ready_;
 
   // The NfcNdefTagTechnology instance that allows users to perform NDEF
   // read and write on this tag.
   scoped_ptr<NfcNdefTagTechnologyChromeOS> ndef_technology_;
 
   // List of observers interested in event notifications from us.
-  ObserverList<device::NfcTag::Observer> observers_;
+  base::ObserverList<device::NfcTag::Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(NfcTagChromeOS);
 };
 
 }  // namespace chromeos
 
 #endif  // DEVICE_NFC_NFC_TAG_CHROMEOS_H_