chromeos: Add power supply info reading capability

chrome/browser/chromeos/cros/power_library.h

 // Copyright (c) 2011 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_
 #pragma once
 
 // TODO(sque): Move to chrome/browser/chromeos/system, crosbug.com/16558
 
 #include "base/callback.h"
+#include "chrome/browser/chromeos/dbus/power_manager_client.h"
 
 namespace base {
 class TimeDelta;
 }
 
 namespace chromeos {
 
 typedef base::Callback<void(int64_t)> CalculateIdleTimeCallback;
+struct PowerStatus;
 
 struct PowerSupplyStatus {
   bool line_power_on;
 
   bool battery_is_present;
   bool battery_is_full;
 
   // Time in seconds until the battery is empty or full, 0 for unknown.
   int64 battery_seconds_to_empty;
   int64 battery_seconds_to_full;
 
   double battery_percentage;
 
   PowerSupplyStatus() : line_power_on(false),
                         battery_is_present(false),
                         battery_is_full(false),
                         battery_seconds_to_empty(0),
                         battery_seconds_to_full(0),
                         battery_percentage(0) {}
+
+  const std::string& ToString() const;
 };
 
 // This interface defines interaction with the ChromeOS power library APIs.
 // Classes can add themselves as observers. Users can get an instance of this
 // library class like this: chromeos::CrosLibrary::Get()->GetPowerLibrary()
-class PowerLibrary {
+class PowerLibrary : public PowerManagerClient::Observer {
  public:
   class Observer {
    public:
     virtual void PowerChanged(const PowerSupplyStatus& status) = 0;
     virtual void SystemResumed() = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
@@ skipping 13 matching lines @@
 
   // Requests restart of the system.
   virtual void RequestRestart() = 0;
 
   // Requests shutdown of the system.
   virtual void RequestShutdown() = 0;
 
   // UI initiated request for status update.
   virtual void RequestStatusUpdate() = 0;
 
+  // Requests power supply info.
+  virtual void UpdatePowerStatus(const PowerStatus& status) = 0;
+
+
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via CrosLibrary::Get().
   static PowerLibrary* GetImpl(bool stub);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_CROS_POWER_LIBRARY_H_