This CL propagates a "closed" signal from DTLS up to the SCTP section of the data channel controller, where it causes closing of all open datachannels. Bug: chromium:1030631, webrtc:10360 Change-Id: I88bb9e1aff5c25f330edfd092ef609d4fcc3a9f8 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/162206 Reviewed-by: Steve Anton <steveanton@webrtc.org> Commit-Queue: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30099}