HLS Iframe only track can't be played since 1.2.0.alpha01 #1150

Version

Media3 1.2.0

More version details

The HLS IFrame only track can be played on r1.1.1, same track can't be played since media3 r1.2.0-alpha01.

Devices that reproduce the issue

On android mobile, tablet and STB.

Tested on mobile: pixel 7, pixel tablet. amazon fireTV 4k stb.

Devices that do not reproduce the issue

No response

Reproducible in the demo app?

Yes

Reproduction steps

Add Iframe only track stream into demo media.exolist.json, and play the demo app to play the iframe only track.
Any version before (include) r1.1.1, can play IFrame only track.
But since r1.2.0-alpha01, the stream can't be played, and no exception to throw.

Expected result

The IFrame only track can be played.

Actual result

Segment downloaded, but nothing rendered.

Media

iframe_only_xmap.zip
iframe_only.zip
Here are two Iframe only tracks.

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.