Predator and CL did not provide any possible suspects.
Using Code Search for the file, "VisiblePosition.cpp" assigning to the concern owner.
Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/3e09fda31d18ff70813be2060b2213b44b83a351

@xiaochengh -- 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 472221:472281.

Detailed report: https://clusterfuzz.com/testcase?key=6661877974433792

Fuzzer: ochang_domfuzzer
Job Type: linux_tsan_chrome_mp
Platform Id: linux

Crash Type: CHECK failure
Crash Address: 
Crash State:
  position_with_affinity.IsConnected(). BLOCKQUOTE@offsetInAnchor[0]/TextAffinity:
  
Sanitizer: thread (TSAN)

Regressed: https://clusterfuzz.com/revisions?job=linux_tsan_chrome_mp&range=472186:472205
Fixed: https://clusterfuzz.com/revisions?job=linux_tsan_chrome_mp&range=472221:472281

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6661877974433792


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.

ClusterFuzz testcase 6661877974433792 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.