Add support to Battery Status API in blink.

Source/modules/battery/BatteryStatus.h

+// 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.
+
+#ifndef BatteryStatus_h
+#define BatteryStatus_h
+
+#include "wtf/PassOwnPtr.h"
+#include "wtf/RefCounted.h"
+
+namespace WebCore {
+
+class BatteryStatus {
+public:
+    static PassOwnPtr<BatteryStatus> create();
+    static PassOwnPtr<BatteryStatus> create(bool charging, double chargingTime, double dischargingTime, double level);
+
+    bool charging() const { return m_charging; }
+    double chargingTime() const  { return m_chargingTime; }
+    double dischargingTime() const  { return m_dischargingTime; }
+    double level() const  { return m_level; }
+
+private:
+    BatteryStatus();
+    BatteryStatus(bool charging, double chargingTime, double dischargingTime, double level);
+
+    bool m_charging;
+    double m_chargingTime;
+    double m_dischargingTime;
+    double m_level;
+};
+
+} // namespace WebCore
+
+#endif // BatteryStatus_h
+