Add support to Battery Status API in blink.

Source/modules/battery/NavigatorBattery.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 NavigatorBattery_h
+#define NavigatorBattery_h
+
+#include "core/frame/Navigator.h"
+#include "platform/Supplementable.h"
+
+namespace WebCore {
+
+class BatteryManager;
+class Navigator;
+
+class NavigatorBattery : public Supplement<Navigator> {
+public:
+    virtual ~NavigatorBattery();
+
+    static NavigatorBattery& from(Navigator&);
+
+    static BatteryManager* battery(Navigator&);
+    BatteryManager* batteryManager(Navigator&);
+
+private:
+    explicit NavigatorBattery();

[Inactive, 2014/03/06 13:45:39]

A bit odd to make this constructor explicit since it has no argument

+    static const char* supplementName();
+
+    RefPtr<BatteryManager> m_batteryManager;
+};
+
+} // namespace WebCore
+
+#endif // NavigatorBattery_h