The previous setup is wacky, and can cause the notification to reach the state machine before the promise rejection, which causes us to stall intermittently. We also take the opportunity to be a bit less trigger happy when we fire it in MediaSourceReader.cpp.
This has two implications:
1. We no longer need to pipe mQueuedSeekTarget through MDSM::Seek to get the appropriate clamping.
2. MDSM::Seek doesn't _need_ to be called on the main thread anymore.
The ogg reader makes two adjustments to the seek time - the first is to clamp it between start and end time, which MDSM already does. The second is to subtract SEEK_OPUS_PREROLL from the target. If we wanted to, we could return this as the resolve value in the seek promise and handle the update in the MDSM. But DropVideoUpToSeekTarget should actually handle this just fine.
This is necessary because we're going to want to start disconnecting sample and seek requests directly from the state machine thread, and the machinery asserts that disconnection happens on the same thread as resolution.
trav90
wolfbeast
Moonchild