Simplify LoadableTextTrack construction

Source/core/html/HTMLTrackElement.cpp

 /*
  * Copyright (C) 2011 Google 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 106 matching lines @@
 String HTMLTrackElement::kind()
 {
     return track()->kind();
 }
 
 void HTMLTrackElement::setKind(const String& kind)
 {
     setAttribute(kindAttr, kind);
 }
 
-String HTMLTrackElement::srclang() const
-{
-    return getAttribute(srclangAttr);
-}
-
-void HTMLTrackElement::setSrclang(const String& srclang)
-{
-    setAttribute(srclangAttr, srclang);
-}
-
-String HTMLTrackElement::label() const
-{
-    return getAttribute(labelAttr);
-}
-
-void HTMLTrackElement::setLabel(const String& label)
-{
-    setAttribute(labelAttr, label);
-}
-
 LoadableTextTrack* HTMLTrackElement::ensureTrack()
 {
     if (!m_track) {
-        // The kind attribute is an enumerated attribute, limited only to know values. It defaults to 'subtitles' if missing or invalid.
-        String kind = getAttribute(kindAttr).lower();
-        if (!TextTrack::isValidKindKeyword(kind))
-            kind = TextTrack::subtitlesKeyword();
-        m_track = LoadableTextTrack::create(this, kind, label(), srclang());
+        // kind, label and language are updated by parseAttribute
+        m_track = LoadableTextTrack::create(this);
     }
     return m_track.get();
 }
 
 TextTrack* HTMLTrackElement::track()
 {
     return ensureTrack();
 }
 
 bool HTMLTrackElement::isURLAttribute(const Attribute& attribute) const
@@ skipping 164 matching lines @@
 HTMLMediaElement* HTMLTrackElement::mediaElement() const
 {
     Element* parent = parentElement();
     if (parent && parent->isMediaElement())
         return toHTMLMediaElement(parentNode());
     return 0;
 }
 
 }