Generate and assign media track ids in demuxers.

media/base/media_track.cc

Index: media/base/media_track.cc
diff --git a/media/base/media_track.cc b/media/base/media_track.cc
index 54aeb76ec21b4de4c12ede6fe6c99c8e584d0762..f46dc3c9502ea0c480fa361e4522201544afd6e5 100644
--- a/media/base/media_track.cc
+++ b/media/base/media_track.cc
@@ -15,8 +15,19 @@ MediaTrack::MediaTrack(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