Revert of Generalize and refactor DeviceSensorEvent* architecture to support multi-event type targets.

Source/core/frame/DeviceEventDispatcherBase.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 DeviceEventDispatcherBase_h
-#define DeviceEventDispatcherBase_h
-
-#include "wtf/Vector.h"
-
-namespace WebCore {
-class DeviceEventControllerBase;
-
-class DeviceEventDispatcherBase {
-public:
-    void addController(DeviceEventControllerBase*);
-    void removeController(DeviceEventControllerBase*);
-
-protected:
-    DeviceEventDispatcherBase();
-    virtual ~DeviceEventDispatcherBase();
-
-    void notifyControllers();
-
-    virtual void startListening() = 0;
-    virtual void stopListening() = 0;
-
-private:
-    void purgeControllers();
-
-    Vector<DeviceEventControllerBase*> m_controllers;
-    bool m_needsPurge;
-    bool m_isDispatching;
-};
-
-} // namespace WebCore
-
-#endif // DeviceEventDispatcherBase_h