p#682 Fix shutdown crash flushing peer connection stats

LLWebRTCImpl::terminate() only posted the peer connection closes to the
signaling thread, so they ran behind the BlockingCall that releases the
factory -- after the factory and device module were gone, or not at all
if the thread was destroyed with the task still queued.

That matters for stats: PeerConnection::Close() flushes any in-flight
GetStats request and delivers the report inline, and our callback walks
mSignalingObserverList to hand it to the viewer.  By then the viewer's
LLVoiceWebRTCConnection objects have been destroyed -- on shutdown they
deliberately skip unsetSignalingObserver, on the assumption that
llwebrtc::terminate() already finished the job -- so the stats callback
reaches into freed memory.

Split the close out of LLWebRTCPeerConnectionImpl::terminate() into
closeOnSignalingThread() and run it from a BlockingCall, so connections
are closed and destroyed on the signaling thread before the factory, the
device module or the observers go away.  Also take ownership of the
connection list up front so the detached thread in the timeout path
isn't racing the main thread over it, clear the observer lists as part
of the close, and skip the observer notification for a stats report
delivered while shutting down.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions