Convert legacy 'native code' to JS-forms in dart:html

lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate

Index: lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate
diff --git a/lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate b/lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate
index b69ac65b3605c76a0dfe0fe3b460308475a9f134..41b068dbb9eada8732955a9fa9a7f409d4cf2725 100644
--- a/lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate
+++ b/lib/html/templates/html/dart2js/factoryprovider_TextTrackCue.darttemplate
@@ -5,12 +5,19 @@
 class $FACTORYPROVIDER {
   static TextTrackCue createTextTrackCue(
       String id, num startTime, num endTime, String text,
-      [String settings, bool pauseOnExit])
-      native '''
-        if (settings == null)
-          return new TextTrackCue(id, startTime, endTime, text);
-        if (pauseOnExit == null)
-          return new TextTrackCue(id, startTime, endTime, text, settings);
-        return new TextTrackCue(id, startTime, endTime, text, settings, pauseOnExit);
-      ''';
+      [String settings, bool pauseOnExit]) {
+        if (settings == null) {
+          return JS('TextTrackCue',
+                    'new TextTrackCue(#,#,#,#)',
+                    id, startTime, endTime, text);
+        }
+        if (pauseOnExit == null) {
+          return JS('TextTrackCue',
+                    'new TextTrackCue(#,#,#,#,#)',
+                    id, startTime, endTime, text, settings);
+        }
+        return JS('TextTrackCue',
+                  'new TextTrackCue(#,#,#,#,#,#)',
+                  id, startTime, endTime, text, settings, pauseOnExit);
+  }
 }