--- a/dom/media/tests/mochitest/dataChannel.js
+++ b/dom/media/tests/mochitest/dataChannel.js
@@ -179,13 +179,13 @@ var commandsCheckLargeXfer = [
       ok(result.data instanceof Blob, "Received data is of instance Blob");
       is(result.data.size, size, "Received data has the correct size.");
     });
   },
 ];
 
 function addInitialDataChannel(chain) {
   chain.insertBefore('PC_LOCAL_CREATE_OFFER', commandsCreateDataChannel);
-  chain.insertBefore('PC_LOCAL_CHECK_MEDIA_TRACKS', commandsWaitForDataChannel);
+  chain.insertBefore('PC_LOCAL_WAIT_FOR_MEDIA_FLOW', commandsWaitForDataChannel);
   chain.removeAfter('PC_REMOTE_CHECK_ICE_CONNECTIONS');
   chain.append(commandsCheckLargeXfer);
   chain.append(commandsCheckDataChannel);
 }

--- a/dom/media/tests/mochitest/pc.js
+++ b/dom/media/tests/mochitest/pc.js
@@ -404,16 +404,17 @@ function(peer, desc, stateExpected) {
            "mismatch between event received " + state +
            " and event expected " + stateExpected);
       }
     };
   });
 
   var stateChanged = peer.setRemoteDescription(desc).then(() => {
     peer.setRemoteDescDate = new Date();
+    peer.checkMediaTracks();
   });
 
   return Promise.all([eventFired, stateChanged]);
 };
 
 /**
  * Adds and removes steps to/from the execution chain based on the configured
  * testOptions.
@@ -1124,38 +1125,34 @@ PeerConnectionWrapper.prototype = {
     var observedKind = track.kind;
     var expectedKind = expectedTrackInfoById[track.id].type;
     is(observedKind, expectedKind,
         "track id " + track.id + " was of kind " +
         observedKind + ", which matches " + expectedKind);
     observedTrackInfoById[track.id] = expectedTrackInfoById[track.id];
   },
 
+  isTrackOnPC: function(track) {
+    return this._pc.getRemoteStreams().some(stream => {
+      return stream.getTracks().some(pcTrack => pcTrack.id == track.id);
+    });
+  },
+
   allExpectedTracksAreObserved: function(expected, observed) {
     return Object.keys(expected).every(trackId => observed[trackId]);
   },
 
   setupTrackEventHandler: function() {
-    var resolveAllTrackEventsDone;
-
-    // checkMediaTracks waits on this promise later on in the test.
-    this.allTrackEventsDonePromise =
-      new Promise(resolve => resolveAllTrackEventsDone = resolve);
-
     this._pc.addEventListener('track', event => {
       info(this + ": 'ontrack' event fired for " + JSON.stringify(event.track));
 
       this.checkTrackIsExpected(event.track,
                                 this.expectedRemoteTrackInfoById,
                                 this.observedRemoteTrackInfoById);
-
-      if (this.allExpectedTracksAreObserved(this.expectedRemoteTrackInfoById,
-                                            this.observedRemoteTrackInfoById)) {
-        resolveAllTrackEventsDone();
-      }
+      ok(this.isTrackOnPC(event.track), "Found track " + event.track.id);
 
       this.ensureMediaElement(event.track, event.streams[0], 'remote');
     });
   },
 
   /**
    * Either adds a given ICE candidate right away or stores it to be added
    * later, depending on the state of the PeerConnection.
@@ -1327,33 +1324,28 @@ PeerConnectionWrapper.prototype = {
     });
 
     Object.keys(this.expectedLocalTrackInfoById).forEach(
         id => ok(observed[id], this + " local id " + id + " was observed"));
   },
 
   /**
    * Checks that we are getting the media tracks we expect.
-   *
-   * @param {object} constraints
-   *        The media constraints of the remote peer connection object
    */
   checkMediaTracks : function() {
     this.checkLocalMediaTracks();
 
     info(this + " Checking remote tracks " +
          JSON.stringify(this.expectedRemoteTrackInfoById));
 
-    // No tracks are expected
-    if (this.allExpectedTracksAreObserved(this.expectedRemoteTrackInfoById,
-                                          this.observedRemoteTrackInfoById)) {
-      return;
-    }
-
-    return timerGuard(this.allTrackEventsDonePromise, 60000, "The expected ontrack events never fired");
+    ok(this.allExpectedTracksAreObserved(this.expectedRemoteTrackInfoById,
+                                         this.observedRemoteTrackInfoById),
+       "All expected tracks have been observed"
+       + "\nexpected: " + JSON.stringify(this.expectedRemoteTrackInfoById)
+       + "\nobserved: " + JSON.stringify(this.observedRemoteTrackInfoById));
   },
 
   checkMsids: function() {
     var checkSdpForMsids = (desc, expectedTrackInfo, side) => {
       Object.keys(expectedTrackInfo).forEach(trackId => {
         var streamId = expectedTrackInfo[trackId].streamId;
         ok(desc.sdp.match(new RegExp("a=msid:" + streamId + " " + trackId)),
            this + ": " + side + " SDP contains stream " + streamId +
@@ -1369,17 +1361,21 @@ PeerConnectionWrapper.prototype = {
 
   markRemoteTracksAsNegotiated: function() {
     Object.values(this.observedRemoteTrackInfoById).forEach(
         trackInfo => trackInfo.negotiated = true);
   },
 
   rollbackRemoteTracksIfNotNegotiated: function() {
     Object.keys(this.observedRemoteTrackInfoById).forEach(
-        id => delete this.observedRemoteTrackInfoById[id]);
+        id => {
+          if (!this.observedRemoteTrackInfoById[id].negotiated) {
+            delete this.observedRemoteTrackInfoById[id];
+          }
+        });
   },
 
   /**
    * Check that media flow is present on the given media element by waiting for
    * it to reach ready state HAVE_ENOUGH_DATA and progress time further than
    * the start of the check.
    *
    * This ensures, that the stream being played is producing

--- a/dom/media/tests/mochitest/templates.js
+++ b/dom/media/tests/mochitest/templates.js
@@ -374,16 +374,17 @@ var commandsPeerConnectionOfferAnswer = 
   function PC_LOCAL_SET_REMOTE_DESCRIPTION(test) {
     return test.setRemoteDescription(test.pcLocal, test._remote_answer, STABLE)
       .then(() => {
         is(test.pcLocal.signalingState, STABLE,
            "signalingState after local setRemoteDescription is 'stable'");
       })
       .then(() => test.pcLocal.markRemoteTracksAsNegotiated());
   },
+
   function PC_REMOTE_SANE_LOCAL_SDP(test) {
     test.pcRemote.localRequiresTrickleIce =
       sdputils.verifySdp(test._remote_answer, "answer",
                          test._offer_constraints, test._offer_options,
                          test.testOptions);
   },
   function PC_LOCAL_SANE_REMOTE_SDP(test) {
     test.pcLocal.remoteRequiresTrickleIce =
@@ -408,24 +409,16 @@ var commandsPeerConnectionOfferAnswer = 
   function PC_LOCAL_VERIFY_ICE_GATHERING(test) {
     return waitForAnIceCandidate(test.pcLocal);
   },
 
   function PC_REMOTE_VERIFY_ICE_GATHERING(test) {
     return waitForAnIceCandidate(test.pcRemote);
   },
 
-  function PC_LOCAL_CHECK_MEDIA_TRACKS(test) {
-    return test.pcLocal.checkMediaTracks();
-  },
-
-  function PC_REMOTE_CHECK_MEDIA_TRACKS(test) {
-    return test.pcRemote.checkMediaTracks();
-  },
-
   function PC_LOCAL_WAIT_FOR_MEDIA_FLOW(test) {
     return test.pcLocal.waitForMediaFlow();
   },
 
   function PC_REMOTE_WAIT_FOR_MEDIA_FLOW(test) {
     return test.pcRemote.waitForMediaFlow();
   },
 

--- a/dom/media/tests/mochitest/test_peerConnection_addDataChannel.html
+++ b/dom/media/tests/mochitest/test_peerConnection_addDataChannel.html
@@ -13,18 +13,18 @@
 
   var test;
   runNetworkTest(function (options) {
     test = new PeerConnectionTest(options);
     addRenegotiation(test.chain,
                      commandsCreateDataChannel,
                      commandsCheckDataChannel);
 
-    // Insert before the second PC_LOCAL_CHECK_MEDIA_TRACKS
-    test.chain.insertBefore('PC_LOCAL_CHECK_MEDIA_TRACKS',
+    // Insert before the second PC_LOCAL_WAIT_FOR_MEDIA_FLOW
+    test.chain.insertBefore('PC_LOCAL_WAIT_FOR_MEDIA_FLOW',
                             commandsWaitForDataChannel,
                             false,
                             1);
 
     test.setMediaConstraints([{audio: true}], [{audio: true}]);
     test.run();
   });
 

--- a/dom/media/tests/mochitest/test_peerConnection_addDataChannelNoBundle.html
+++ b/dom/media/tests/mochitest/test_peerConnection_addDataChannelNoBundle.html
@@ -24,18 +24,18 @@
                          },
                          function PC_REMOTE_EXPECT_ICE_CHECKING(test) {
                            test.pcRemote.iceCheckingRestartExpected = true;
                          },
                        ]
                       ),
                      commandsCheckDataChannel);
 
-    // Insert before the second PC_LOCAL_CHECK_MEDIA_TRACKS
-    test.chain.insertBefore('PC_LOCAL_CHECK_MEDIA_TRACKS',
+    // Insert before the second PC_LOCAL_WAIT_FOR_MEDIA_FLOW
+    test.chain.insertBefore('PC_LOCAL_WAIT_FOR_MEDIA_FLOW',
                             commandsWaitForDataChannel,
                             false,
                             1);
 
     test.setMediaConstraints([{audio: true}], [{audio: true}]);
     test.run();
   });