This is the first and last macro that will go into this project,
but it's really useful to verify that a call returns an optional
value (that is non-nullopt) and that extracts the underlying type.
Bug: webrtc:12614
Change-Id: I0a05bf22466a575dbcc9a8f7b88dde0f55ff54d9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/213345
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33607}
