Yet another prerequisite for replacing RTCStatsMember<T> with absl::optional<T>, but this looks like the last one. Bug: webrtc:15164 Change-Id: I2cde51e8c8c951f71b48ccd45e07146091a99616 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/334647 Commit-Queue: Henrik Boström <hbos@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#41541}