Motown: Convert MediaSink to expose MediaTimelineControlSite

mojo/services/media/common/interfaces/media_state.mojom

-// 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.
-
-[DartPackage="mojo_services"]
-module mojo.media;
-
-// Expresses the overall state of a media component.
-enum MediaState {
-  // Unable to function due to error. Fault details are provided elsewhere.
-  // TODO(dalesat): Eliminate this state.
-  FAULT,
-
-  // Requires preparation in order to function.
-  UNPREPARED,
-
-  // Prepared, rate zero (paused).
-  PAUSED,
-
-  // Prepared, rate non-zero.
-  PLAYING,
-
-  // Stopped playing because end-of-stream was encountered.
-  ENDED,
-};