Add support to Battery Status API in blink.

Source/modules/battery/BatteryManager.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 BatteryManager_h
+#define BatteryManager_h
+
+#include "core/dom/ContextLifecycleObserver.h"
+#include "core/dom/Document.h"
+#include "core/events/EventTarget.h"
+#include "modules/battery/BatteryStatus.h"
+
+namespace WebCore {
+
+class Navigator;
+
+class BatteryManager : public ContextLifecycleObserver, public RefCounted<BatteryManager>, public EventTarget {
+public:
+    virtual ~BatteryManager();
+    static PassRefPtr<BatteryManager> create(ExecutionContext*);
+
+    // EventTarget implementation.
+    virtual const WTF::AtomicString& interfaceName() const { return EventTargetNames::BatteryManager; }
+    virtual ExecutionContext* executionContext() const OVERRIDE FINAL { return ContextLifecycleObserver::executionContext(); }
+
+    // ContextLifecycleObserver
+    virtual void contextDestroyed() OVERRIDE;
+
+    bool charging();
+    double chargingTime();
+    double dischargingTime();
+    double level();
+
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(chargingchange);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(chargingtimechange);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(dischargingtimechange);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(levelchange);
+
+    void didChangeBatteryStatus(PassRefPtr<Event>, PassOwnPtr<BatteryStatus>);
+
+    using RefCounted<BatteryManager>::ref;
+    using RefCounted<BatteryManager>::deref;
+
+protected:
+    virtual EventTargetData* eventTargetData() { return &m_eventTargetData; }
+    virtual EventTargetData& ensureEventTargetData() { return m_eventTargetData; }
+
+private:
+    explicit BatteryManager(ExecutionContext*);
+
+    // EventTarget implementation.
+    virtual void refEventTarget() { ref(); }
+    virtual void derefEventTarget() { deref(); }
+
+    EventTargetData m_eventTargetData;
+    OwnPtr<BatteryStatus> m_batteryStatus;
+};
+
+}
+
+#endif // BatteryManager_h
+