Sync audio/video/text track-related interfaces with the specs

Source/core/html/track/vtt/VTTRegionList.idl

Index: Source/core/html/track/vtt/VTTRegionList.idl
diff --git a/Source/core/html/track/vtt/VTTRegionList.idl b/Source/core/html/track/vtt/VTTRegionList.idl
index cdd3d4dd13125a81942b42efd317afbf0e736b30..080b103656fe428fca61d2b2e890798d82c8c5da 100644
--- a/Source/core/html/track/vtt/VTTRegionList.idl
+++ b/Source/core/html/track/vtt/VTTRegionList.idl
@@ -23,6 +23,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+// TODO(philipj): The VTTRegionList interface has been removed from the spec:
+// https://www.w3.org/Bugs/Public/show_bug.cgi?id=24380
+
 [
     RuntimeEnabled=WebVTTRegions,
     WillBeGarbageCollected,
@@ -31,4 +34,3 @@
     getter VTTRegion item(unsigned long index);
     VTTRegion getRegionById(DOMString id);
 };
-