Because representation is now unset on stream deactivation,
we need to force selecting one.

We'll need such overridable method if reselecting a stream
requires global playlist action/refresh.

Since smooth adds new segments from segments data,
we need to resync for unselected streams.

With multiple audio tracks, es would select another when deleting
current es/not recyling.

Recent changes deselects representation on stream deactivation.
But setPosition requires representation when reactivating a stream.

ref #14972
ref #10328

Manager took ownership of logic

The callbacks return nothing (unlike drain), so they can be treated
identically regardless of the ES category.

So long as the flag is only polled, this is a little bit simpler.
(Though ideally, it would probably not be polled.)

This restores the ability to flush the decoder while it is paused.

This works around a deadlock in the ES output. When paused, buffering
cannot be measured since output latency is unknown. Even decoding
latency would be unrepresentative.

The paused flag is no longer protected by the owner lock (the FIFO lock
instead), and it is no longer useful to clear it at exit.

Edited-and-...
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Test media subitems when parsing a directory via a path, via a fd and via
various locations.

The decoder can be paused by the decoder owner while the decoder thread
is decoding. We still need to queue the last decoded picture(s) to the
(not yet paused) video output.