revert: getPlayheadTimeAsDate() differs from X-EXT-PROGRAM-DATE-TIME (#…

…6330)

This reverts 776b69d

Closes #6317
Closes #6299
Reopening issue #5939

lib/hls/hls_parser.js

@@ -984,22 +984,6 @@ shaka.hls.HlsParser = class {
         this.presentationTimeline_.setSegmentAvailabilityDuration(
             segmentAvailabilityDuration);
       }
-
-      if (!this.presentationTimeline_.isStartTimeLocked()) {
-        const streamInfos = Array.from(this.uriToStreamInfosMap_.values());
-        const activeStreamInfos =
-            streamInfos.filter((s) => s.stream.segmentIndex);
-        for (const streamInfo of activeStreamInfos) {
-          if (streamInfo.type != 'audio' && streamInfo.type != 'video') {
-            continue;
-          }
-          const firstReference = streamInfo.stream.segmentIndex.get(0);
-          if (firstReference && firstReference.syncTime) {
-            const syncTime = firstReference.syncTime;
-            this.presentationTimeline_.setPresentationStartTime(syncTime);
-          }
-        }
-      }
     } else {
       // Use the minimum duration as the presentation duration.
       this.presentationTimeline_.setDuration(this.getMinDuration_());

lib/media/presentation_timeline.js

@@ -328,17 +328,6 @@ shaka.media.PresentationTimeline = class {
   }
 
 
-  /**
-   * Returns if the presentation timeline's start time is locked.
-   *
-   * @return {boolean}
-   * @export
-   */
-  isStartTimeLocked() {
-    return this.startTimeLocked_;
-  }
-
-
   /**
    * Gives PresentationTimeline a Stream's minimum segment start time.
    *