Thanks for showing an interest in this.

Consider adding it as a WPT to https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/external/wpt/webrtc/RTCPeerConnection-setRemoteDescription-tracks.https.html.

For WPT, don't rely on Chrome-only APIs.
- Use addTrack instead of addStream. addStream is not in the spec and is implemented on top of addTrack, so calling addTrack directly should trigger the same problem.
- Remove the parameter of createOffer ({offerToReceiveAudio: true, offerToReceiveVideo: true})

(The former, addStream, is not in the spec anymore. The latter is actually in the spec, https://w3c.github.io/webrtc-pc/#legacy-configuration-extensions, but under legacy section. But it is also irrelevant to the bug.)

That particular file I referenced uses async_test(). Prefer promise_test() so you don't have to explicitly call t.done().

Also prefer using async and await when possible, though in this case it is important that you do not await the SRD when calling addStream() and createOffer().

ninja -C out/Debug -j 2000 blink_tests
out/Debug/content_shell --run-layout-test external/wpt/webrtc/RTCPeerConnection-setRemoteDescription-tracks.https.html

See also external/wpt/webrtc/RTCPeerConnection-setRemoteDescription-tracks.https-expected.txt.

For reference:
The parent commit of the fix is 2485344d4e8792bc4f9716deadda41fbc0d89ad9. If running the layout tests against this commit, the layout test script is in another location:
blink/tools/run_layout_tests.sh

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bd3afeb02abdef655457ada0c1f87b58cb06f805

commit bd3afeb02abdef655457ada0c1f87b58cb06f805
Author: Kristoffer Erlandsson <kerl@google.com>
Date: Wed May 16 09:39:20 2018

Add test to verify a particular PeerConnection setup does not deadlock

Does the connection setup in a specific sequence that historically
triggered a deadlock ( https://crbug.com/736725 ). The test simply
verifies this specific sequence completes without errors or timeout.

Verified it fails on the deadlock by running the test on the parent commit
(2485344d4e8792bc4f9716deadda41fbc0d89ad9) of the original bug fix.

BUG= chromium:840737 

Change-Id: I93d9d8cb50cad9629268971520de489450d8649b
Reviewed-on: https://chromium-review.googlesource.com/1057249
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Commit-Queue: Kristoffer Erlandsson <kerl@google.com>
Cr-Commit-Position: refs/heads/master@{#559022}
[add] https://crrev.com/bd3afeb02abdef655457ada0c1f87b58cb06f805/third_party/WebKit/LayoutTests/external/wpt/webrtc/RTCPeerConnection-add-track-no-deadlock.https.html

Shall we delete the fast/peerconnection/ version while we're at it?

WDYM fast/peerconnection/?

I just uploaded https://crrev.com/c/1061174 removing the browser test variant that is not needed now, if that is what you mean?

Yes that's it, I meant browser test not fast/peerconnection/.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b93b64e20199275c0a6a73c927374ad74c41d20e

commit b93b64e20199275c0a6a73c927374ad74c41d20e
Author: Kristoffer Erlandsson <kerl@google.com>
Date: Wed May 16 11:27:09 2018

Remove browser test that was converted to layout test.

This test was converted to a layout test in https://crrev.com/c/1057249.

BUG= chromium:840737 

Change-Id: Iebed1ea6f8707928e3b5cfcb2fff5e21bb8c159b
Reviewed-on: https://chromium-review.googlesource.com/1061174
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Commit-Queue: Kristoffer Erlandsson <kerl@google.com>
Cr-Commit-Position: refs/heads/master@{#559039}
[delete] https://crrev.com/f83a17e827e8dc5b18c2f191df8067a18c2f6949/content/browser/webrtc/webrtc_add_stream_no_deadlock_browsertest.cc
[modify] https://crrev.com/b93b64e20199275c0a6a73c927374ad74c41d20e/content/test/BUILD.gn
[delete] https://crrev.com/f83a17e827e8dc5b18c2f191df8067a18c2f6949/content/test/data/media/peerconnection-add-stream.html