Source/modules/screen_orientation/ScreenOrientationDispatcher.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 ScreenOrientationDispatcher_h
#define ScreenOrientationDispatcher_h

#include "core/frame/PlatformEventDispatcher.h"

namespace blink {

class FrameView;
class ScreenOrientation;

// ScreenOrientationDispatcher is a singleton that handles whether the current
// Blink instance should be listening to the screen orientation platform events.
// It is not a common implementation of PlatformEventDispatcher in the sense
// that it doesn't actually dispatch events but simply start/stop listening. The
// reason being that screen orientation events are always sent to the WebFrame's
// but some platforms require to poll to have an accurate reporting. When
// ScreenOrientationDispatcher is listening, that means that the platform should
// be polling if required.
class ScreenOrientationDispatcher FINAL :
    public PlatformEventDispatcher {
public:
    static ScreenOrientationDispatcher& instance();

private:
    ScreenOrientationDispatcher();
    virtual ~ScreenOrientationDispatcher();

    // Inherited from PlatformEventDispatcher.
    virtual void startListening() OVERRIDE;
    virtual void stopListening() OVERRIDE;
};

} // namespace blink

#endif // ScreenOrientationDispatcher_h