Add Dispatcher class to the Battery Status API module.

Source/modules/battery/BatteryDispatcher.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 BatteryDispatcher_h
+#define BatteryDispatcher_h
+
+#include "core/frame/DeviceSensorEventDispatcher.h"
+#include "modules/battery/BatteryManager.h"
+#include "modules/battery/BatteryStatus.h"
+#include "public/platform/WebBatteryListener.h"
+
+namespace blink {
+class WebBatteryStatus;
+}
+
+namespace WebCore {
+
+class BatteryDispatcher FINAL : public DeviceSensorEventDispatcher, public blink::WebBatteryListener {
+public:
+    static BatteryDispatcher& instance();
+    virtual ~BatteryDispatcher();
+
+    void addClient(BatteryManager*);
+    void removeClient(BatteryManager*);
+
+    const BatteryStatus* getLatestData();
+    virtual void updateBatteryStatus(const blink::WebBatteryStatus&) OVERRIDE;
+
+private:
+    BatteryDispatcher();
+
+    void didChangeBatteryStatus(const AtomicString& eventType);
+
+    virtual void startListening() OVERRIDE;
+    virtual void stopListening() OVERRIDE;
+
+    RefPtr<BatteryStatus> m_batteryStatus;
+};
+
+}
+
+#endif // BatteryDispatcher_h