Fix is about to land in webrtc, chromium fix in progress, we should consider merging these into M72.

The following revision refers to this bug:
  https://webrtc.googlesource.com/src.git/+/afa07dda42c9253a37d1c220e71e2c79df90d8d7

commit afa07dda42c9253a37d1c220e71e2c79df90d8d7
Author: Henrik Boström <hbos@webrtc.org>
Date: Thu Dec 20 13:01:58 2018

[Unified Plan] SRD: Always set associated remote streams.

This fixes a bug where the streams are not updated if the "msid" changes
without triggering "ontrack", such as if the streams associated with a
receiver changes while the receiver is active.

Bug:  webrtc:10083 ,  chromium:916934 
Change-Id: Ic7b19ad5ef648ed6880cae4157bf49f8435467ae
Reviewed-on: https://webrtc-review.googlesource.com/c/114161
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Seth Hampson <shampson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26069}
[modify] https://crrev.com/afa07dda42c9253a37d1c220e71e2c79df90d8d7/pc/peerconnection.cc
[modify] https://crrev.com/afa07dda42c9253a37d1c220e71e2c79df90d8d7/pc/peerconnection.h
[modify] https://crrev.com/afa07dda42c9253a37d1c220e71e2c79df90d8d7/pc/peerconnection_rtp_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c33c286e565fc89faaa492178a3b4ba7cf666ae8

commit c33c286e565fc89faaa492178a3b4ba7cf666ae8
Author: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Date: Thu Dec 20 18:34:55 2018

Roll src/third_party/webrtc 9a4f38ec5c4a..3793bb447ae5 (8 commits)

https://webrtc.googlesource.com/src.git/+log/9a4f38ec5c4a..3793bb447ae5


git log 9a4f38ec5c4a..3793bb447ae5 --date=short --no-merges --format='%ad %ae %s'
2018-12-20 nisse@webrtc.org Refactor TestVideoCapturer to support multiple sinks.
2018-12-20 ssilkin@webrtc.org Update number of spatial layers if SS is available.
2018-12-20 srte@webrtc.org Adds flag to customize output root dir in scenario tests.
2018-12-20 srte@webrtc.org Adds support for empty key fields in field trial parser.
2018-12-20 hbos@webrtc.org [Unified Plan] SRD: Always set associated remote streams.
2018-12-20 srte@webrtc.org Stop using deprecated PacedSender method from RtpTransportControllerSend.
2018-12-20 nisse@webrtc.org Refactor NetEqDecoderPlc to use AudioDecoderProxyFactory
2018-12-20 srte@webrtc.org Removes return value and Try prefix from TryDeliverPacket.


Created with:
  gclient setdep -r src/third_party/webrtc@3793bb447ae5

The AutoRoll server is located here: https://autoroll.skia.org/r/webrtc-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:linux_chromium_archive_rel_ng;luci.chromium.try:mac_chromium_archive_rel_ng

BUG= chromium:916934 
TBR=webrtc-chromium-sheriffs-robots@google.com

Change-Id: Idaf600f08455b6b520d6cdae738c8cf881d30baa
Reviewed-on: https://chromium-review.googlesource.com/c/1387186
Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#618278}
[modify] https://crrev.com/c33c286e565fc89faaa492178a3b4ba7cf666ae8/DEPS

This was the second CL that landed for this issue, I forgot to reference this bug from it:
https://chromium-review.googlesource.com/c/chromium/src/+/1384257

Requesting to merge third_party/webrtc CL in #2 and chromium CL in #4 to M-72.

This bug requires manual review: DEPS changes referenced in bugdroid comments.
Please contact the milestone owner if you have questions.
Owners: govind@(Android), kariahda@(iOS), djmm@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Note this merge has priority for WebRTC as we have planned to switch simultaneously with Safari to the new SDP format for web compact reasons. See https://webrtc.org/web-apis/chrome/unified-plan/

Pls apply appropriate OSs label.

Pls merge your change to M72 branch 3626 ASAP so we can pick it up for next Beta release. Thank you.

Thank you, will do. Is the next Beta release the 9th?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97dd55252be171ede829e9d57acdb199ddc6832f

commit 97dd55252be171ede829e9d57acdb199ddc6832f
Author: Henrik Boström <hbos@chromium.org>
Date: Fri Jan 04 11:32:33 2019

Surface associated remote stream MSID changes for active receivers.

Previously, associated media streams were only updated on the
"addition" and "removal" of a track. But MSIDs can change for active
receivers as well. In this CL, we always update the associated media
streams based on the state of the webrtc-layer receiver.

TBR=hbos@chromium.org

(cherry picked from commit 05c7d3b938defb3ce4043e09d1ca839264b4c2e9)

Bug:  webrtc:10083 ,  chromium:916934 
Change-Id: I54bb00a5077a0b7b78964faf13882055c8101427
Reviewed-on: https://chromium-review.googlesource.com/c/1384257
Commit-Queue: Henrik Boström <hbos@chromium.org>
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#618333}
Reviewed-on: https://chromium-review.googlesource.com/c/1396142
Reviewed-by: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#559}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
[modify] https://crrev.com/97dd55252be171ede829e9d57acdb199ddc6832f/third_party/blink/renderer/modules/peerconnection/rtc_peer_connection.cc
[modify] https://crrev.com/97dd55252be171ede829e9d57acdb199ddc6832f/third_party/blink/renderer/modules/peerconnection/rtc_peer_connection.h

#13 is the chromium merge and this is the webrtc merge: https://webrtc-review.googlesource.com/c/src/+/116180