This allows implementing custom clients for test in peer connection scenario tests. For example server side behavior. Bug: webrtc:10839 Change-Id: I5627b7a4d967d401f31d2e9a8f861d0849eb0184 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/151907 Commit-Queue: Sebastian Jansson <srte@webrtc.org> Reviewed-by: Per Kjellander <perkj@webrtc.org> Cr-Commit-Position: refs/heads/master@{#29125}