chromium/src/third_party/blink/renderer/modules/media_controls/elements/media_control_animation_event_listener.h

// Copyright 2017 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 THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIA_CONTROLS_ELEMENTS_MEDIA_CONTROL_ANIMATION_EVENT_LISTENER_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIA_CONTROLS_ELEMENTS_MEDIA_CONTROL_ANIMATION_EVENT_LISTENER_H_

#include "third_party/blink/renderer/core/dom/events/native_event_listener.h"
#include "third_party/blink/renderer/modules/modules_export.h"

namespace blink {

class Element;
class ExecutionContext;
class Event;

// Listens for animationend and animationiteration DOM events on a HTML element
// provided by the loading panel. When the events are called it calls the
// OnAnimation* methods on the loading panel.
//
// This exists because we need to know when the animation ends so we can reset
// the element and we also need to keep track of how many iterations the
// animation has gone through so we can nicely stop the animation at the end of
// the current one.
class MODULES_EXPORT MediaControlAnimationEventListener final
    : public NativeEventListener {
 public:
  // To use this class you need to use Observer as a mixin and return an element
  // to watch. You then instanitate a MediaControlAnimationEventListener from
  // the class pointing to your observer. The listener will call the On*
  // functions when events are triggered.
  class MODULES_EXPORT Observer : public GarbageCollectedMixin {
   public:
    // The watched element has completed an iteration of an animation.
    virtual void OnAnimationIteration() = 0;

    // The watched element has finished all iterations of an animation.
    virtual void OnAnimationEnd() = 0;

    // This is the element to watch for animation events.
    virtual Element& WatchedAnimationElement() const = 0;

    void Trace(Visitor*) const override;
  };

  explicit MediaControlAnimationEventListener(Observer*);
  void Detach();

  void Trace(Visitor*) const override;

  void Invoke(ExecutionContext*, Event*) override;

 private:
  Member<Observer> observer_;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIA_CONTROLS_ELEMENTS_MEDIA_CONTROL_ANIMATION_EVENT_LISTENER_H_