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

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/cd39e5b0ea3c0da423e54066bd97571f82dffaad

@mlippautz -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

fyi, I am OOO till Wed. Will have a look then.

ClusterFuzz has detected this issue as fixed in range 494105:494239.

Detailed report: https://clusterfuzz.com/testcase?key=5986569923330048

Fuzzer: inferno_twister
Job Type: windows_syzyasan_content_shell
Platform Id: windows

Crash Type: Null-dereference
Crash Address: 0x00000108
Crash State:
  blink::EventTarget::TraceWrappers
  blink::ScriptWrappableVisitor::DispatchTraceWrappers
  blink::TraceTrait<blink::DataTransferItemList>::TraceMarkedWrapper
  
Memory Tool: SYZYASAN

Regressed: https://clusterfuzz.com/revisions?job=windows_syzyasan_content_shell&range=493237:493282
Fixed: https://clusterfuzz.com/revisions?job=windows_syzyasan_content_shell&range=494105:494239

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5986569923330048

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.

ClusterFuzz testcase 5986569923330048 is verified as fixed, so closing issue as verified.

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

This locally showed up with a slightly different stack trace that I believe is better.

==1==ERROR: AddressSanitizer: use-after-poison on address 0x7ea4883070d0 at pc 0x7fb372b09b1e bp 0x7fffac45abf0 sp 0x7fffac45abe8
READ of size 8 at 0x7ea4883070d0 thread T0 (content_shell)
==1==WARNING: invalid path to external symbolizer!
==1==WARNING: Failed to use and restart external symbolizer!
    #0 0x7fb372b09b1d in operator* third_party/WebKit/Source/platform/heap/Member.h:83:34
    #1 0x7fb372b09b1d in blink::EventListenerIterator::NextListener() third_party/WebKit/Source/core/events/EventListenerMap.cpp:244:0
    #2 0x7fb372b22ec8 in blink::EventTarget::TraceWrappers(blink::WrapperVisitor const*) const third_party/WebKit/Source/core/events/EventTarget.cpp:160:45
    #3 0x7fb374604d4e in blink::TraceTrait<blink::Clipboard>::TraceMarkedWrapper(blink::WrapperVisitor const*, void const*) third_party/WebKit/Source/platform/heap/TraceTraits.h:244:12
    #4 0x7fb36fb37c15 in TraceWrappers third_party/WebKit/Source/platform/bindings/ScriptWrappableVisitor.h:42:7
    #5 0x7fb36fb37c15 in blink::ScriptWrappableVisitor::AdvanceTracing(double, v8::EmbedderHeapTracer::AdvanceTracingActions) third_party/WebKit/Source/platform/bindings/ScriptWrappableVisitor.cpp:201:0
    #6 0x7fb3771f93c9 in v8::internal::MarkCompactCollector::ProcessEphemeralMarking(bool) v8/src/heap/mark-compact.cc:2007:46

We fixed "blink::Clipboard" just recently.