--- a/dom/media/tests/mochitest/test_peerConnection_addtrack_removetrack_events.html
+++ b/dom/media/tests/mochitest/test_peerConnection_addtrack_removetrack_events.html
@@ -52,21 +52,16 @@ runNetworkTest(function (options) {
                  "Expected event to be instance of MediaStreamTrackEvent");
               is(trackEvent.type, "addtrack",
                  "Expected addtrack event type");
               is(test.pcRemote.getWebrtcTrackId(trackEvent.track), newTrack.id, "Expected track in event");
               is(trackEvent.track.readyState, "live",
                  "added track should be live");
             })
             .then(() => haveNoEvent(remoteStream, "addtrack"));
-
-          remoteStream.addEventListener("removetrack",
-                                        function onRemovetrack(trackEvent) {
-            ok(false, "UA shouldn't raise 'removetrack' when receiving peer connection");
-          })
         });
       },
     ],
     [
       function PC_REMOTE_CHECK_EVENTS(test) {
         return eventsPromise;
       },
     ]

--- a/dom/media/tests/mochitest/test_peerConnection_removeThenAddAudioTrack.html
+++ b/dom/media/tests/mochitest/test_peerConnection_removeThenAddAudioTrack.html
@@ -9,18 +9,18 @@
   createHTML({
     bug: "1017888",
     title: "Renegotiation: remove then add audio track"
   });
 
   runNetworkTest(function (options) {
     const test = new PeerConnectionTest(options);
     let originalTrack;
-    let haveMuteEvent;
-    let haveUnmuteEvent;
+    let haveMuteEvent = new Promise(() => {});
+    let haveUnmuteEvent = new Promise(() => {});
     addRenegotiation(test.chain,
       [
         function PC_REMOTE_FIND_RECEIVER(test) {
           is(test.pcRemote._pc.getReceivers().length, 1,
              "pcRemote should have one receiver");
           originalTrack = test.pcRemote._pc.getReceivers()[0].track;
         },
         function PC_LOCAL_REMOVE_AUDIO_TRACK(test) {
@@ -59,20 +59,25 @@
           const analyser = new AudioStreamAnalyser(
               new AudioContext(), new MediaStream([track]));
           const freq = analyser.binIndexForFrequency(TEST_AUDIO_FREQ);
           return analyser.waitForAnalysisSuccess(arr => arr[freq] < 50);
         }
       ]
     );
 
-    test.chain.insertBefore("PC_REMOTE_SET_LOCAL_DESCRIPTION", [
+    // Second negotiation should cause the first track to mute...
+    test.chain.insertBefore("PC_REMOTE_SET_REMOTE_DESCRIPTION", [
       function PC_REMOTE_SETUP_ONMUTE(test) {
         haveMuteEvent = haveEvent(test.pcRemote._pc.getReceivers()[0].track, "mute");
-      },
+      }
+    ], false, 1);
+
+    // ...and a second track to unmute.
+    test.chain.insertAfter("PC_REMOTE_SET_REMOTE_DESCRIPTION", [
       function PC_REMOTE_SETUP_ONUNMUTE(test) {
         haveUnmuteEvent = haveEvent(test.pcRemote._pc.getReceivers()[1].track, "unmute");
       }
     ], false, 1);
 
     test.setMediaConstraints([{audio: true}], [{audio: true}]);
     test.run();
   });

--- a/dom/media/tests/mochitest/test_peerConnection_removeThenAddVideoTrack.html
+++ b/dom/media/tests/mochitest/test_peerConnection_removeThenAddVideoTrack.html
@@ -11,18 +11,18 @@
     bug: "1017888",
     title: "Renegotiation: remove then add video track"
   });
 
   runNetworkTest(function (options) {
     const test = new PeerConnectionTest(options);
     const helper = new VideoStreamHelper();
     var originalTrack;
-    let haveMuteEvent;
-    let haveUnmuteEvent;
+    let haveMuteEvent = new Promise(() => {});
+    let haveUnmuteEvent = new Promise(() => {});
     addRenegotiation(test.chain,
       [
         function PC_REMOTE_FIND_RECEIVER(test) {
           is(test.pcRemote._pc.getReceivers().length, 1,
              "pcRemote should have one receiver");
           originalTrack = test.pcRemote._pc.getReceivers()[0].track;
         },
         function PC_LOCAL_REMOVE_VIDEO_TRACK(test) {
@@ -61,20 +61,25 @@
 
           const vAdded = test.pcRemote.remoteMediaElements.find(
               elem => elem.id.includes(track.id));
           return helper.checkVideoPaused(vAdded, 10, 10, 16, 5000);
         }
       ]
     );
 
-    test.chain.insertBefore("PC_REMOTE_SET_LOCAL_DESCRIPTION", [
+    // Second negotiation should cause the first track to mute...
+    test.chain.insertBefore("PC_REMOTE_SET_REMOTE_DESCRIPTION", [
       function PC_REMOTE_SETUP_ONMUTE(test) {
         haveMuteEvent = haveEvent(test.pcRemote._pc.getReceivers()[0].track, "mute");
-      },
+      }
+    ], false, 1);
+
+    // ...and a second track to unmute.
+    test.chain.insertAfter("PC_REMOTE_SET_REMOTE_DESCRIPTION", [
       function PC_REMOTE_SETUP_ONUNMUTE(test) {
         haveUnmuteEvent = haveEvent(test.pcRemote._pc.getReceivers()[1].track, "unmute");
       }
     ], false, 1);
 
     test.setMediaConstraints([{video: true}], [{video: true}]);
     test.run();
   });