blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/html/shadow/MediaControlsWindowEventListener.h

 // Copyright 2016 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 MediaControlsWindowEventListener_h
 #define MediaControlsWindowEventListener_h
 
 #include "core/events/EventListener.h"
 #include "wtf/Functional.h"
 
 namespace blink {
 
 class MediaControls;
-class LocalDOMWindow;
 
 class MediaControlsWindowEventListener final : public EventListener {
  public:
   using Callback = Function<void(), WTF::SameThreadAffinity>;
 
   static MediaControlsWindowEventListener* create(MediaControls*,
                                                   std::unique_ptr<Callback>);
 
   bool operator==(const EventListener&) const override;
 
   void start();
   void stop();
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   explicit MediaControlsWindowEventListener(MediaControls*,
                                             std::unique_ptr<Callback>);
 
   void handleEvent(ExecutionContext*, Event*) override;
 
   Member<MediaControls> m_mediaControls;
   std::unique_ptr<Callback> m_callback;
   bool m_isActive;
 };
 
 }  // namespace blink
 
 #endif  // MediaControlsWindowEventListener_h