Predator and CL could not provide any possible suspects.

Using Code Search for the file, "font_fallback_linux.cc" and observed there was some recent changes for the below file.

Suspect CL: 
https://chromium.googlesource.com/chromium/src/+/8b49ef62009b10e8644ef1040daef993b1ee6d64

drott@ -- Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Thanks!

ClusterFuzz has detected this issue as fixed in range 549059:549062.

Detailed report: https://clusterfuzz.com/testcase?key=5555999154110464

Fuzzer: libFuzzer_renderer_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  FcCharSetHasChar
  gfx::CachedFont::HasGlyphForCharacter
  gfx::CachedFontSet::GetFallbackFontForChar
  
Sanitizer: undefined (UBSAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_ubsan&range=525942:525946
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_ubsan&range=549059:549062

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5555999154110464

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reference.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 5555999154110464 is verified as fixed, so closing issue as verified.

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