Uncomment IDL fragments which we used to fail to parse.

Source/WebCore/html/HTMLTrackElement.idl

 /*
  * 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 20 matching lines @@
         attribute [Reflect, URL] DOMString src;
         attribute DOMString kind;
         attribute DOMString srclang;
         attribute DOMString label;
         attribute [Reflect=default] boolean isDefault;
 
         const unsigned short NONE = 0;
         const unsigned short LOADING = 1;
         const unsigned short LOADED = 2;
         // Reflect is used for ERROR because it conflicts with a windows define.
-// FIXME(antonm)
-#if 0
         [Reflect=TRACK_ERROR] const unsigned short ERROR = 3;
-#endif
         readonly attribute unsigned short readyState;
 
         readonly attribute TextTrack track;
 };
 }