Bug 1259788 - Remove direct track listeners from TrackUnionStream before inputs are removed. r=jesup

MozReview-Commit-ID: DTHF2pHEFSt

--HG--
extra : rebase_source : feddfc8ddbae33b2c97d0009b2a648ca71b33bbe

dom/media/TrackUnionStream.cpp

@@ -58,6 +58,10 @@ TrackUnionStream::TrackUnionStream() :
       if (mTrackMap[i].mInputPort == aPort) {
         STREAM_LOG(LogLevel::Debug, ("TrackUnionStream %p removing trackmap entry %d", this, i));
         EndTrack(i);
+        for (auto listener : mTrackMap[i].mOwnedDirectListeners) {
+          // Remove listeners while the entry still exists.
+          RemoveDirectTrackListenerImpl(listener, mTrackMap[i].mOutputTrackID);
+        }
         mTrackMap.RemoveElementAt(i);
       }
     }
@@ -130,6 +134,10 @@ TrackUnionStream::TrackUnionStream() :
         allFinished = false;
       }
       if (!mappedTracksWithMatchingInputTracks[i]) {
+        for (auto listener : mTrackMap[i].mOwnedDirectListeners) {
+          // Remove listeners while the entry still exists.
+          RemoveDirectTrackListenerImpl(listener, mTrackMap[i].mOutputTrackID);
+        }
         mTrackMap.RemoveElementAt(i);
       }
     }