Remove unused includes from core/html .cpp files

Source/core/html/track/TextTrack.cpp

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) 2011, 2012, 2013 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 15 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "core/html/track/TextTrack.h"
 
-#include "core/dom/Event.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/track/TextTrackCueList.h"
 #include "core/html/track/TextTrackList.h"
-#include "core/html/track/TextTrackRegionList.h"
 #include "core/html/track/TrackBase.h"
 
 namespace WebCore {
 
 static const int invalidTrackIndex = -1;
 
 const AtomicString& TextTrack::subtitlesKeyword()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, subtitles, ("subtitles", AtomicString::ConstructFromLiteral));
     return subtitles;
@@ skipping 435 matching lines @@
 {
     // "Main program" content is intrinsic to the presentation of the media file, regardless of locale. Content such as
     // directors commentary is not "main program" because it is not essential for the presentation. HTML5 doesn't have
     // a way to express this in a machine-reable form, it is typically done with the track label, so we assume that caption
     // tracks are main content and all other track types are not.
     return m_kind == captionsKeyword();
 }
 
 } // namespace WebCore