Don't set negative values to setWhen()

When the 'when' timer of the notification is disabled
`DefaultMediaNotificationProvider` may set `C.TIME_UNSET`
as the time. Users reported problems on some devices with
this and the docs ask for an event time that probably
shouldn't be a negative number.

This change sets `0L` instead of `C.TIME_UNSET` when the
timer is disabled.

Issue: androidx/media#903

#minor-release

PiperOrigin-RevId: 594451074

RELEASENOTES.md

@@ -117,6 +117,9 @@
         [#802](https://github.com/androidx/media/issues/802)).
     *   Fix broadcasting `notifyChildrenChanged` for legacy controllers
         ([#644](https://github.com/androidx/media/issues/644)).
+    *   Fix a bug where setting a negative time for a disabled `setWhen` timer
+        of the notification caused a crash on some devices
+        ([#903](https://github.com/androidx/media/issues/903)).
 *   UI:
     *   Fix issue where forward and rewind buttons are not visible when used
         with Material Design in a BottomSheetDialogFragment

libraries/session/src/main/java/androidx/media3/session/DefaultMediaNotificationProvider.java

@@ -375,7 +375,7 @@ public class DefaultMediaNotificationProvider implements MediaNotification.Provi
     long playbackStartTimeMs = getPlaybackStartTimeEpochMs(player);
     boolean displayElapsedTimeWithChronometer = playbackStartTimeMs != C.TIME_UNSET;
     builder
-        .setWhen(playbackStartTimeMs)
+        .setWhen(displayElapsedTimeWithChronometer ? playbackStartTimeMs : 0L)
         .setShowWhen(displayElapsedTimeWithChronometer)
         .setUsesChronometer(displayElapsedTimeWithChronometer);