ref(TPC): Do not add/remove video tracks from TPC for unmute/mute case on Safari.

 Only add/remove the tracks from the peerconnection so that the camera led turns off on mute.

modules/RTC/TPCUtils.js

             return Promise.resolve();
         }
 
-        return transceiver.sender.replaceTrack(track)
-            .then(() => {
-                this.pc.localTracks.set(localTrack.rtcId, localTrack);
-            });
+        return transceiver.sender.replaceTrack(track);
     }
 
     /**
     /**
      * Removes the track from the RTCRtpSender as part of the mute operation.
      * @param {JitsiLocalTrack} localTrack - track to be removed.
-     * @returns {Promise<boolean>} - Promise that resolves to false if unmute
-     * operation is successful, a reject otherwise.
+     * @returns {Promise<void>} - resolved when done.
      */
     removeTrackMute(localTrack) {
         const mediaType = localTrack.getType();
 
         logger.debug(`Removing ${localTrack} on ${this.pc}`);
 
-        return transceiver.sender.replaceTrack(null)
-            .then(() => {
-                this.pc.localTracks.delete(localTrack.rtcId);
-
-                return Promise.resolve(false);
-            });
+        return transceiver.sender.replaceTrack(null);
     }
 
     /**
         const transceivers = this.pc.peerconnection.getTransceivers()
             .filter(t => t.receiver && t.receiver.track && t.receiver.track.kind === mediaType);
         const localTracks = this.pc.getLocalTracks(mediaType);
-        logger.info(`${active ? 'Enabling' : 'Suspending'} ${mediaType} media transfer on ${this.pc}`);
 
+        logger.info(`${active ? 'Enabling' : 'Suspending'} ${mediaType} media transfer on ${this.pc}`);
         transceivers.forEach((transceiver, idx) => {
             if (active) {
                 // The first transceiver is for the local track and only this one can be set to 'sendrecv'

modules/RTC/TraceablePeerConnection.js

  * Promise is rejected when something goes wrong.
  */
 TraceablePeerConnection.prototype.addTrackUnmute = function(track) {
-    if (browser.usesUnifiedPlan()) {
-        return this.tpcUtils.addTrackUnmute(track);
-    }
     if (!this._assertTrackBelongs('addTrackUnmute', track)) {
         // Abort
         return Promise.reject('Track not found on the peerconnection');
 
         return Promise.reject('Stream not found');
     }
+
+    if (browser.usesUnifiedPlan()) {
+        return this.tpcUtils.addTrackUnmute(track);
+    }
+
     this._addStream(webRtcStream);
 
     return Promise.resolve(true);
  * Promise is rejected when something goes wrong.
  */
 TraceablePeerConnection.prototype.removeTrackMute = function(localTrack) {
-    if (browser.usesUnifiedPlan()) {
-        return this.tpcUtils.removeTrackMute(localTrack);
-    }
     const webRtcStream = localTrack.getOriginalStream();
 
     this.trace(
         // Abort - nothing to be done here
         return Promise.reject('Track not found in the peerconnection');
     }
+
+    if (browser.usesUnifiedPlan()) {
+        return this.tpcUtils.removeTrackMute(localTrack);
+    }
+
     if (webRtcStream) {
         logger.info(
             `Removing ${localTrack} as mute from ${this}`);