Per the latest WebRTC stats spec (https://w3c.github.io/webrtc-stats/#dom-rtcicecandidatestats) the address field of a peer-reflexive remote candidate should be concealed until the same address is learnt via addIceCandidate. This CL also refactors the sanitization-related code paths. Bug: chromium:968161 Change-Id: I74c5da78232b2f604689867bda2937b8af827c4f Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/149381 Reviewed-by: Steve Anton <steveanton@webrtc.org> Commit-Queue: Qingsi Wang <qingsi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#28909}