Bug 1275596 - Ignore ended tracks when selecting new track in MediaStreamAudioSourceNode and MediaElementSourceNode. r=padenot

This is how it was meant to work when the refactor landed in Bug 1208371.
We have no test coverage of seeking apparently.

MozReview-Commit-ID: IhyGbjctO7E

--HG--
extra : rebase_source : 70f1ab777d8f7d6632d24f7134415ad13f73d166

dom/media/webaudio/MediaStreamAudioSourceNode.cpp

@@ -117,11 +117,14 @@ MediaStreamAudioSourceNode::AttachToFirstTrack(const RefPtr<DOMMediaStream>& aMe
   nsTArray<RefPtr<AudioStreamTrack>> tracks;
   aMediaStream->GetAudioTracks(tracks);
 
-  if (tracks.IsEmpty()) {
+  for (const RefPtr<AudioStreamTrack>& track : tracks) {
+    if (track->Ended()) {
+      continue;
+    }
+
+    AttachToTrack(track);
     return;
   }
-
-  AttachToTrack(tracks[0]);
 }
 
 void