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/ActiveDOMObject.h"
+#include "core/events/EventTarget.h"
+#include "core/frame/Frame.h"
+#include "modules/battery/BatteryStatus.h"
+
+namespace WebCore {
+
+class Navigator;
+class ScriptExecutionContext;
+
+class BatteryManager : public ActiveDOMObject, public RefCounted<BatteryManager>, public EventTarget {

[abarth-chromium, 2014/02/28 06:45:14]

Please remove the ActiveDOMObject base class.  It's not needed in this CL.  We
can add it once its needed.  For now, you just need to be a
ContextDestructionObserver.

+public:
+    virtual ~BatteryManager();
+    static PassRefPtr<BatteryManager> create(Frame*);

[abarth-chromium, 2014/02/28 06:45:14]

This should probably be constructed from a Document rather than a Frame

+
+    // EventTarget implementation.
+    virtual const WTF::AtomicString& interfaceName() const { return EventTargetNames::BatteryManager; }
+    virtual ExecutionContext* executionContext() const OVERRIDE FINAL { return ActiveDOMObject::executionContext(); }

[abarth-chromium, 2014/02/28 06:45:14]

The reason you should use a Document as the context object is because this
function makes you specific to a given Document.

+
+    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;
+
+    // ActiveDOMObject implementation.
+    virtual bool canSuspend() const { return true; }
+    virtual void suspend() OVERRIDE;
+    virtual void resume() OVERRIDE;
+    virtual void stop() OVERRIDE;
+
+protected:
+    virtual EventTargetData* eventTargetData() { return &m_eventTargetData; }
+    virtual EventTargetData& ensureEventTargetData() { return m_eventTargetData; }
+
+private:
+    explicit BatteryManager(Navigator*);
+    explicit BatteryManager(Frame*);

[abarth-chromium, 2014/02/28 06:45:14]

You've still got two constructors.  You only need one.

+
+    // EventTarget implementation.
+    virtual void refEventTarget() { ref(); }
+    virtual void derefEventTarget() { deref(); }
+
+    EventTargetData m_eventTargetData;
+    OwnPtr<BatteryStatus> m_batteryStatus;
+};
+
+}
+
+#endif // BatteryManager_h
+