Apply toFoo generation macro to TrackBase classes

Source/bindings/core/v8/custom/V8TrackEventCustom.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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 33 matching lines @@
     TrackEvent* trackEvent = V8TrackEvent::toNative(info.Holder());
     TrackBase* track = trackEvent->track();
 
     if (!track) {
         v8SetReturnValueNull(info);
         return;
     }
 
     switch (track->type()) {
     case TrackBase::TextTrack:
-        v8SetReturnValueFast(info, static_cast<TextTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toTextTrack(track), trackEvent);
         return;
 
     case TrackBase::AudioTrack:
-        v8SetReturnValueFast(info, static_cast<AudioTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toAudioTrack(track), trackEvent);
         return;
 
     case TrackBase::VideoTrack:
-        v8SetReturnValueFast(info, static_cast<VideoTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toVideoTrack(track), trackEvent);
         return;
     }
 
     v8SetReturnValueNull(info);
 }
 
 } // namespace WebCore