When receiving the `onTimelineChanged` callback, we convert the timeline to the list of `QueueItem`s, where decoding a bitmap is needed for building each of the `QueueItem`s. The strategy is similar to what we did in <unknown commit> for list of `MediaBrowserCompat.MediaItem` - set the queue item list until the bitmaps decoding for all the `MediaItem`s are completed.
PiperOrigin-RevId: 490283587
(cherry picked from commit 8ce1213d)
