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

Suspecting Commit#
https://skia.googlesource.com/skia.git/+/44acb5b09bb87163bc9c010be915b3f33e3157eb

@bsalomon -- 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 491008:491056.

Detailed report: https://clusterfuzz.com/testcase?key=4740882858508288

Fuzzer: libFuzzer_paint_op_buffer_fuzzer
Job Type: mac_libfuzzer_chrome_asan
Platform Id: mac

Crash Type: Bus
Crash Address: 0x6310fffffef5
Crash State:
  GrAtlasTextBlob::Run::SubRunInfo::maskFormat
  GrAtlasTextBlob::appendGlyph
  GrTextUtils::BmpAppendGlyph
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=489564:489568
Fixed: https://clusterfuzz.com/revisions?job=mac_libfuzzer_chrome_asan&range=491008:491056

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=4740882858508288


See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.md for more information.

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