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

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/3faa815b598a801f6b65a32d8d776411c102766f

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

@msrchandra It seems this bug could happen even in stable situations, so I think it's not caused by my patch (https://chromium.googlesource.com/chromium/src/+/3faa815b598a801f6b65a32d8d776411c102766f), and also the test case seems unusual HTML. 
Thank you for reaching out!

Lower to Pri-3 since real world usage of "InsertHTML" command with uneditable TABLE
is low.

ClusterFuzz has detected this issue as fixed in range 496287:501540.

Detailed report: https://clusterfuzz.com/testcase?key=6562013299081216

Fuzzer: ochang_domfuzzer
Job Type: linux_asan_chrome_v8_arm
Platform Id: linux

Crash Type: Null-dereference READ
Crash Address: 0x00000010
Crash State:
  blink::RootEditableElement
  blink::DeleteSelectionCommand::RemoveRedundantBlocks
  blink::DeleteSelectionCommand::DoApply
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=linux_asan_chrome_v8_arm&range=488849:488980
Fixed: https://clusterfuzz.com/revisions?job=linux_asan_chrome_v8_arm&range=496287:501540

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6562013299081216

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.

ClusterFuzz testcase 6562013299081216 is verified as fixed, so closing issue as verified.

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