Refactor "track options" to be a dictionary.

third_party/WebKit/Source/modules/mediastream/MediaStreamConstraints.idl

-/*
- * Copyright (C) 2012 Google Inc. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- */
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-MediaStreamConstraints
 
 dictionary MediaStreamConstraints {
-    (boolean or Dictionary) video = false;
-    (boolean or Dictionary) audio = false;
+  (boolean or MediaTrackConstraintSet) video;
+  (boolean or MediaTrackConstraintSet) audio;
 };