Add [TypeChecking=Interface] to the TextTrack interface

LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html

Index: LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html
diff --git a/LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html b/LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html
index e6eb37ae0b760c05384c2a8835401bbb801bb8ec..635efe8d63853fc3003a84afb9140dcabf23fa52 100644
--- a/LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html
+++ b/LayoutTests/media/track/opera/interfaces/TextTrack/addCue.html
@@ -45,6 +45,13 @@ test(function() {
     t1.addCue(c1);
     assert_equals(t1.cues.length, 1, 't1.cues.length after second addition');
 }, document.title+', adding an associated but removed cue to the same track');
+test(function() {
+    var t1 = video.addTextTrack('subtitles');
+    assert_equals(t1.cues.length, 0);
+    assert_throws(new TypeError, function() { t1.addCue(null); }, 'null');
+    assert_throws(new TypeError, function() { t1.addCue([]); }, 'non-TextTrackCue');
+    assert_equals(t1.cues.length, 0);
+}, document.title+', invalid values');
 
 var t = async_test(document.title+', adding a cue associated with a track element to other track');
 t.step(function(){