This reduces code duplication and ensures common behavior
between the unit classes.
Bug: webrtc:9709
Change-Id: I9529ef10b3f538355f53250a2b67c6b4e250cce8
Reviewed-on: https://webrtc-review.googlesource.com/c/110901
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25690}
