Implement automatically generated constructors for frog and dartium dart:html

client/dom/templates/html/frog/factoryprovider_TextTrackCue.darttemplate

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class $FACTORYPROVIDER {
+  factory TextTrackCue(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);
+  ''';
+}