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

Suspecting Commit#
https://chromium.googlesource.com/chromium/src/+/c8070f461957f5f2aaaf41147538ebe811b4abce

@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/+/284327b9335ac93de792685b6012fbcd47af01e8

commit 284327b9335ac93de792685b6012fbcd47af01e8
Author: Xiaocheng Hu <xiaochengh@chromium.org>
Date: Mon Sep 04 12:37:56 2017

Apply stricter destination validity check when moving paragraphs

CompositeEditCommand::MoveParagraphs() used to abort when the move
destination is in the range of paragraphs to be moved, exclusively.

This patch changes the abort condition to an inclusive one, since
there is a crash found when the destination equals one of the
moving range boundaries.

Bug:  761280 
Change-Id: I9cd48c04cc8574c245defd5cc961538c870ec1dc
Reviewed-on: https://chromium-review.googlesource.com/648261
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#499488}
[modify] https://crrev.com/284327b9335ac93de792685b6012fbcd47af01e8/third_party/WebKit/Source/core/editing/commands/ApplyStyleCommandTest.cpp
[modify] https://crrev.com/284327b9335ac93de792685b6012fbcd47af01e8/third_party/WebKit/Source/core/editing/commands/CompositeEditCommand.cpp

ClusterFuzz has detected this issue as fixed in range 499408:499633.

Detailed report: https://clusterfuzz.com/testcase?key=5762855243874304

Fuzzer: inferno_layout_test_unmodified
Job Type: mac_asan_content_shell
Platform Id: mac

Crash Type: Null-dereference READ
Crash Address: 0x000000000000
Crash State:
  blink::TextIteratorAlgorithm<blink::EditingAlgorithm<blink::NodeTraversal> >::Te
  blink::TextIteratorAlgorithm<blink::EditingAlgorithm<blink::NodeTraversal> >::Ra
  blink::CompositeEditCommand::MoveParagraphs
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=mac_asan_content_shell&range=450347:450401
Fixed: https://clusterfuzz.com/revisions?job=mac_asan_content_shell&range=499408:499633

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5762855243874304

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 5762855243874304 is verified as fixed, so closing issue as verified.

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