Find it and CL did not provide any possible suspects.
Using Code Search for the file, "MediaStream.cpp" assigning to the concern owner.

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/d4833220d8d9320deb606a0068a332a046486c95

@haraken -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

ClusterFuzz has detected this issue as fixed in range 441524:441984.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6131627978915840

Fuzzer: lcamtuf_cross_fuzz
Job Type: mac_asan_chrome
Platform Id: mac

Crash Type: UNKNOWN READ
Crash Address: 0x000000000061
Crash State:
  blink::MediaStream::trackEnded
  blink::MediaStreamTrack::propagateTrackEnded
  blink::MediaStreamSource::setReadyState
  
Sanitizer: address (ASAN)

Regressed: https://cluster-fuzz.appspot.com/revisions?job=mac_asan_chrome&range=438498:440663
Fixed: https://cluster-fuzz.appspot.com/revisions?job=mac_asan_chrome&range=441524:441984

Minimized Testcase (20.03 Kb): https://cluster-fuzz.appspot.com/download/AMIfv94fxVNxvpyZKW3Lk2KifNiDernro2T1qrtmQBlClvIrOcr8j_P4K_OGilywzyZM-7mpLfwkrBYgP-8RI-WXohEKcwPhujQMVVUnKcMU1csDt-_ngTJod6kVPye3-t1fffQP344BsFrYEUTJvM1CBOUhQLzlOJghLugsHEEjGvrgXQcXznc?testcase_id=6131627978915840

See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.