Generate and assign media track ids in demuxers.

media/base/media_track.cc

 // Copyright 2016 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.
 
 #include "media/base/media_track.h"
 
 namespace media {
 
 MediaTrack::MediaTrack(Type type,
                        StreamParser::TrackId byteStreamTrackId,
                        const std::string& kind,
                        const std::string& label,
                        const std::string& lang)
     : type_(type),
       byteStreamTrackId_(byteStreamTrackId),
       kind_(kind),
       label_(label),
-      language_(lang) {}
+      language_(lang),
+      id_("") {}

[xhwang, 2016/06/09 06:06:02]

nit: not necessary

[servolk, 2016/06/09 19:14:46]

Done.

 
 MediaTrack::~MediaTrack() {}
 
+MediaTrack::TrackId MediaTrack::id() const {
+  return id_;
+}
+
+void MediaTrack::setId(TrackId id) {
+  DCHECK(id_ == "");
+  DCHECK(id != "");

[xhwang, 2016/06/09 06:06:02]

nit: use empty()?

[servolk, 2016/06/09 19:14:46]

Done.

+  id_ = id;
+}

[xhwang, 2016/06/09 06:06:02]

nit: These two functions can be inlined in the header

[servolk, 2016/06/09 19:14:46]

Done.

+
 }  // namespace media