chromeos: Simplify power supply info in PowerLibrary

chrome/browser/chromeos/low_battery_observer.h

 // Copyright (c) 2010 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 CHROME_BROWSER_CHROMEOS_LOW_BATTERY_OBSERVER_H_
 #define CHROME_BROWSER_CHROMEOS_LOW_BATTERY_OBSERVER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/time.h"
 #include "chrome/browser/chromeos/cros/power_library.h"
 #include "chrome/browser/chromeos/notifications/system_notification.h"
 
 class Profile;
 
 namespace chromeos {
 
+struct PowerStatus;
+
 // The low battery observer displays a system notification when the battery
 // is low.
 
 class LowBatteryObserver : public PowerLibrary::Observer {
  public:
   explicit LowBatteryObserver(Profile* profile);
   virtual ~LowBatteryObserver();
 
  private:
-  virtual void PowerChanged(PowerLibrary* object);
+  virtual void PowerChanged(const PowerStatus& power_status);
   virtual void SystemResumed() {}
 
   void Show(base::TimeDelta remaining, bool urgent);
   void Hide();
 
   SystemNotification notification_;
   int remaining_;  // Last displayed remaining time in minutes
 
   DISALLOW_COPY_AND_ASSIGN(LowBatteryObserver);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOW_BATTERY_OBSERVER_H_