virtual/override specifier cleanup in device/battery/.

device/battery/battery_status_manager_default.cc

 // 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.
 
 #include "device/battery/battery_status_manager.h"
 
 #include "base/logging.h"
 
 namespace device {
 
 namespace {
 
 class BatteryStatusManagerDefault : public BatteryStatusManager {
  public:
   explicit BatteryStatusManagerDefault(
       const BatteryStatusService::BatteryUpdateCallback& callback) {}
-  virtual ~BatteryStatusManagerDefault() {}
+  ~BatteryStatusManagerDefault() override {}
 
  private:
   // BatteryStatusManager:
-  virtual bool StartListeningBatteryChange() override {
+  bool StartListeningBatteryChange() override {
     NOTIMPLEMENTED();
     return false;
   }
 
-  virtual void StopListeningBatteryChange() override { NOTIMPLEMENTED(); }
+  void StopListeningBatteryChange() override { NOTIMPLEMENTED(); }
 
   DISALLOW_COPY_AND_ASSIGN(BatteryStatusManagerDefault);
 };
 
 }  // namespace
 
 // static
 scoped_ptr<BatteryStatusManager> BatteryStatusManager::Create(
     const BatteryStatusService::BatteryUpdateCallback& callback) {
   return scoped_ptr<BatteryStatusManager>(
       new BatteryStatusManagerDefault(callback));
 }
 
 }  // namespace device