Refactor cros library code into central location and have the UI elements obs...

chrome/browser/chromeos/cros_power_library.h

+// Copyright (c) 2009 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_CROS_POWER_LIBRARY_H_
+#define CHROME_BROWSER_CHROMEOS_CROS_POWER_LIBRARY_H_
+
+#include "base/observer_list.h"
+#include "base/singleton.h"
+#include "base/time.h"
+#include "third_party/cros/chromeos_power.h"
+
+// This class handles the interaction with the ChromeOS power library APIs.
+// Classes can add themselves as observers. Users can get an instance of this
+// library class like this: CrosPowerLibrary::Get()
+class CrosPowerLibrary {
+ public:
+  class Observer {
+   public:
+    virtual void PowerChanged(CrosPowerLibrary* obj) = 0;
+  };
+
+  // This gets the singleton CrosPowerLibrary
+  static CrosPowerLibrary* Get();
+
+  // Returns true if the ChromeOS library was loaded.
+  static bool loaded();
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Whether or not the line power is connected.
+  bool line_power_on() const;
+
+  // Whether or not the battery is fully charged..
+  bool battery_fully_charged() const;
+
+  // The percentage (0-100) of remaining battery.
+  double battery_percentage() const;
+
+  // The amount of time until battery is empty.
+  base::TimeDelta battery_time_to_empty() const;
+
+  // The amount of time until battery is full.
+  base::TimeDelta battery_time_to_full() const;
+
+ private:
+  friend struct DefaultSingletonTraits<CrosPowerLibrary>;
+
+  CrosPowerLibrary();
+  ~CrosPowerLibrary();
+
+  // This method is called when there's a change in power status.
+  // This will notify all the Observers.
+  static void PowerStatusChangedHandler(void* object,
+                                        const chromeos::PowerStatus& status);
+
+  ObserverList<Observer> observers_;
+
+  // A reference to the battery power api, to allow callbacks when the battery
+  // status changes.
+  chromeos::PowerStatusConnection power_status_connection_;
+
+  // The latest power status.
+  chromeos::PowerStatus status_;
+
+  DISALLOW_COPY_AND_ASSIGN(CrosPowerLibrary);
+};
+
+#endif  // CHROME_BROWSER_CHROMEOS_CROS_POWER_LIBRARY_H_