This CL makes it so the caller explicitly has to provide EmulatedRoute instances when creating TcpMessageRoute. Previously those were automatically generated. This means that the EmulatedRoute instances can be reused. Bug: webrtc:9883 Change-Id: I7ad03ca6a5a3dbb91df76e3ca1190a1a75bf0cc5 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/159703 Commit-Queue: Sebastian Jansson <srte@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#29791}