chromeos: Add support for the battery status API on chromeos.

content/browser/battery_status/battery_status_provider_impl.h

+// Copyright (c) 2012 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 CONTENT_BROWSER_BATTERY_STATUS_BATTERY_STATUS_PROVIDER_IMPL_H_
+#define CONTENT_BROWSER_BATTERY_STATUS_BATTERY_STATUS_PROVIDER_IMPL_H_
+
+#include <list>

[jam, 2012/04/12 19:34:55]

nit: not used

[sadrul, 2012/04/12 21:53:24]

Done.

+
+#include "base/memory/singleton.h"
+#include "base/observer_list.h"
+#include "content/public/browser/battery_status_provider.h"
+
+class BatteryStatusProviderImpl : public content::BatteryStatusProvider {
+ public:
+  class Observer {
+   public:
+    virtual void PowerChanged(
+        const content::PowerSupplyStatus& power_status) = 0;
+  };
+
+  static BatteryStatusProviderImpl* GetInstance();
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+ private:
+  friend struct DefaultSingletonTraits<BatteryStatusProviderImpl>;
+
+  // Overridden from BatteryStatusProvider.
+  virtual void SendUpdate(

[jam, 2012/04/12 19:34:55]

nit: why make this private? i'd put it in public, since it's odd that someone
has to cast this to the base interface to call this function (say if android's
impl is in content)

[sadrul, 2012/04/12 21:53:24]

Done.

+      const content::PowerSupplyStatus& power_status) OVERRIDE;
+
+  BatteryStatusProviderImpl();
+  virtual ~BatteryStatusProviderImpl();
+
+  ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(BatteryStatusProviderImpl);
+};
+
+#endif  // CONTENT_BROWSER_BATTERY_STATUS_BATTERY_STATUS_PROVIDER_IMPL_H_