Predator could not provide any possible suspects.
Assigning to concern owner from CL --
https://chromium.googlesource.com/chromium/src/+log/11e185405c47ea292572be82dd8c90617cfead02..1b460e69a28391f0590f61f6ebf5c341d1e7df23?pretty=fuller&n=10000

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/2a88dac7dd3caf5155d4e82f08c86d12484dbf18

@chaopeng -- 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 496881:496921.

Detailed report: https://clusterfuzz.com/testcase?key=5396384407879680

Fuzzer: marty_html_twiddler
Job Type: windows_asan_chrome_no_sandbox
Platform Id: windows

Crash Type: Null-dereference READ
Crash Address: 0x00000008
Crash State:
  blink::ScrollableArea::GetScrollAnimator
  blink::Scrollbar::ScrollableAreaTargetPos
  blink::Scrollbar::ThumbWillBeUnderMouse
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=494105:494239
Fixed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=496881:496921

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5396384407879680

Additional requirements: Requires Gestures

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.