Predator and CL could not provide any possible suspects.
Using Code Search for the file, "LayoutSelection.cpp" assigning to concern owner.

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/de2e1f7c022b7fe489d08a9e4871049969551de4

@yoichio -- 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 496835:496881.

Detailed report: https://clusterfuzz.com/testcase?key=4760396388106240

Fuzzer: ifratric-browserfuzzer-v3
Job Type: windows_asan_chrome_no_sandbox
Platform Id: windows

Crash Type: Null-dereference READ
Crash Address: 0x00000008
Crash State:
  blink::CalcSelectionRangeAndSetSelectionState
  blink::LayoutSelection::Commit
  blink::LayoutView::CommitPendingSelection
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=495902:496126
Fixed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=496835:496881

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=4760396388106240

See https://github.com/google/clusterfuzz-tools for more information.

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