This CL introduces the possibility to save an RTCEventLogs from the call in order to do further analysis and call debugging. Bug: webrtc:10138 Change-Id: If95ef66ecf52218b34ce01a4bcf8ab7991b04e5b Reviewed-on: https://webrtc-review.googlesource.com/c/123881 Reviewed-by: Artem Titov <titovartem@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#26838}