Remove Unused Optional Method Parameter

Because we changed how we collect the streams before downloading we
no longer used the variant id parameter. This change removes the
parameter.

Issue: #1248
Change-Id: Iab4323c7b358ed83812b2ff36e9632022e65f88a

lib/offline/storage.js

@@ -909,12 +909,11 @@ shaka.offline.Storage.prototype.createPeriod_ = function(
  * @param {shakaExtern.Period} period
  * @param {shakaExtern.Stream} stream
  * @param {number} estimatedStreamBandwidth
- * @param {number=} opt_variantId
  * @return {shakaExtern.StreamDB}
  * @private
  */
 shaka.offline.Storage.prototype.createStream_ = function(
-    manifest, period, stream, estimatedStreamBandwidth, opt_variantId) {
+    manifest, period, stream, estimatedStreamBandwidth) {
   /** @type {shakaExtern.StreamDB} */
   let streamDb = {
     id: stream.id,
@@ -936,10 +935,6 @@ shaka.offline.Storage.prototype.createStream_ = function(
     variantIds: []
   };
 
-  if (opt_variantId != null) {
-    streamDb.variantIds.push(opt_variantId);
-  }
-
   /** @type {number} */
   let startTime =
       manifest.presentationTimeline.getSegmentAvailabilityStart();