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

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/849079adeeaa989c2aca2b7aadbf5f7c165773be

@slangley -- 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 499699:499748.

Detailed report: https://clusterfuzz.com/testcase?key=6259028455063552

Fuzzer: meacer_web_ext
Job Type: linux_asan_chrome_mp
Platform Id: linux

Crash Type: Null-dereference READ
Crash Address: 0x000000000008
Crash State:
  blink::QuotaTracker::GetDatabaseSizeAndSpaceAvailableToOrigin
  blink::DatabaseTracker::GetMaxSizeForDatabase
  blink::SQLTransactionBackend::OpenTransactionAndPreflight
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=linux_asan_chrome_mp&range=499162:499170
Fixed: https://clusterfuzz.com/revisions?job=linux_asan_chrome_mp&range=499699:499748

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6259028455063552

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.