This CL is preparation for extraction of public API for network emulation layer. Bug: webrtc:10138 Change-Id: Id59204ea20a103dafce4122c59e51a354836c374 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/126624 Commit-Queue: Artem Titov <titovartem@webrtc.org> Reviewed-by: Sebastian Jansson <srte@webrtc.org> Cr-Commit-Position: refs/heads/master@{#27050}