During SelectConnectionToPing, optional connection had the value of nullptr which led the code to crash. Bug: None Change-Id: Ibe9a54b71bbd62f3b80d676ca80d64ff951dda51 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/206081 Commit-Queue: Tim Na <natim@webrtc.org> Reviewed-by: Jonas Oreland <jonaso@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33197}