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

@palmer -- 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 470995:471049.

Detailed report: https://clusterfuzz.com/testcase?key=5126197150482432

Fuzzer: afl_stylesheet_contents_fuzzer
Job Type: afl_chrome_asan
Platform Id: linux

Crash Type: Direct-leak
Crash Address: 
Crash State:
  PartitionAllocGenericFlags
  PartitionAllocGeneric
  FastMalloc
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=afl_chrome_asan&range=415614:415641
Fixed: https://clusterfuzz.com/revisions?job=afl_chrome_asan&range=470995:471049

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5126197150482432


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.

ClusterFuzz testcase 5126197150482432 is verified as fixed, so closing issue.

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