Replace more ObserverList with base::ObserverList.

ui/events/ozone/device/device_manager_manual.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 UI_EVENTS_OZONE_DEVICE_DEVICE_MANAGER_MANUAL_H_
 #define UI_EVENTS_OZONE_DEVICE_DEVICE_MANAGER_MANUAL_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 14 matching lines @@
  private:
   // DeviceManager overrides:
   void ScanDevices(DeviceEventObserver* observer) override;
   void AddObserver(DeviceEventObserver* observer) override;
   void RemoveObserver(DeviceEventObserver* observer) override;
 
   void OnDevicesScanned(std::vector<base::FilePath>* result);
 
   bool have_scanned_devices_;
   std::vector<base::FilePath> devices_;
-  ObserverList<DeviceEventObserver> observers_;
+  base::ObserverList<DeviceEventObserver> observers_;
 
   base::WeakPtrFactory<DeviceManagerManual> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceManagerManual);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_DEVICE_DEVICE_MANAGER_MANUAL_H_