Predator and CL could not provide any possible suspects.
Using Code Search for the file, "TextIterator.cpp" assigning to the concern owner who might be related.

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

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1c6810ef1c13ded11a414d832386eb535e65d0b8

commit 1c6810ef1c13ded11a414d832386eb535e65d0b8
Author: Xiaocheng Hu <xiaochengh@chromium.org>
Date: Wed Aug 30 04:40:46 2017

Bug fix in CompositeEditCommand::MoveParagraphContentsToNewBlockIfNecessary

This patch fixes a bug in the above function, where the newly inserted
block may not be editable due to style, in which case the editing
command should abort.

Bug:  760042 
Change-Id: I81c83e694054836887cf96d8320e7eae5bbbcf42
Reviewed-on: https://chromium-review.googlesource.com/642054
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498366}
[modify] https://crrev.com/1c6810ef1c13ded11a414d832386eb535e65d0b8/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp
[modify] https://crrev.com/1c6810ef1c13ded11a414d832386eb535e65d0b8/third_party/WebKit/Source/core/editing/commands/CompositeEditCommandTest.cpp

ClusterFuzz has detected this issue as fixed in range 498349:498366.

Detailed report: https://clusterfuzz.com/testcase?key=5464828738273280

Fuzzer: ifratric-browserfuzzer-v3
Job Type: windows_asan_chrome_no_sandbox
Platform Id: windows

Crash Type: Null-dereference READ
Crash Address: 0x00000000
Crash State:
  blink::TextIteratorAlgorithm<class blink::EditingAlgorithm<class blink::NodeTrav
  blink::TextIteratorAlgorithm<class blink::EditingAlgorithm<class blink::NodeTrav
  blink::CompositeEditCommand::MoveParagraphs
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=495902:496126
Fixed: https://clusterfuzz.com/revisions?job=windows_asan_chrome_no_sandbox&range=498349:498366

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5464828738273280

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 5464828738273280 is verified as fixed, so closing issue as verified.

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