Use TextTrackKind enum in HTMLMediaElement.addTextTrack IDL signature

LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html

Index: LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html
diff --git a/LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html b/LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html
index 13a5d6f852e6d692916b7098e5c7f5449999eaa8..6893212aaa1f7e384ce9d2d967363c5389dc45cf 100644
--- a/LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html
+++ b/LayoutTests/media/track/opera/interfaces/HTMLElement/HTMLMediaElement/addTextTrack.html
@@ -6,19 +6,19 @@
 <script>
 var video = document.createElement('video');
 test(function(){
-    assert_throws('SYNTAX_ERR', function(){
+    assert_throws(new TypeError, function(){
         video.addTextTrack('foo');
     });
-    assert_throws('SYNTAX_ERR', function(){
+    assert_throws(new TypeError, function(){
         video.addTextTrack(undefined);
     });
-    assert_throws('SYNTAX_ERR', function(){
+    assert_throws(new TypeError, function(){
         video.addTextTrack(null);
     });
 }, document.title + ' bogus first arg');
 
 test(function(){
-    assert_throws('SYNTAX_ERR', function(){
+    assert_throws(new TypeError, function(){
         video.addTextTrack('SUBTITLES');
     });
 }, document.title + ' uppercase first arg');
@@ -71,8 +71,8 @@ test(function(){
 test(function(){
     var t = video.addTextTrack('subtitles', undefined, undefined);
     assert_equals(t.kind, 'subtitles');
-    assert_equals(t.label, 'undefined');
-    assert_equals(t.language, 'undefined');
+    assert_equals(t.label, '');
+    assert_equals(t.language, '');
     assert_equals(t.mode, 'hidden');
     assert_equals(t.cues.length, 0);
 }, document.title + ' undefined second and third arg');
@@ -104,4 +104,4 @@ test(function(){
     assert_equals(t.cues.length, 0);
 }, document.title + ' foo second arg, third arg omitted');
 
-</script>
+</script>