From the above Chromium change Log suspecting the below.
Review-Url: https://codereview.chromium.org/2734713002
sigbjornf@: Could you please take a look into this if its related to your change.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a9c462ea8bf9588c2a6859e7fe9fde1e4c7f7353

commit a9c462ea8bf9588c2a6859e7fe9fde1e4c7f7353
Author: sigbjornf <sigbjornf@opera.com>
Date: Tue Mar 07 03:40:21 2017

TestInterfaces: support delegate clearing.

Following r454834, the implementation of SetDelegate() also needs to
handle resetting of the test delegate.

R=
BUG= 698713 

Review-Url: https://codereview.chromium.org/2738513004
Cr-Commit-Position: refs/heads/master@{#455030}

[modify] https://crrev.com/a9c462ea8bf9588c2a6859e7fe9fde1e4c7f7353/content/shell/test_runner/test_interfaces.cc

 Issue 699066  has been merged into this issue.

ClusterFuzz has detected this issue as fixed in range 454873:455052.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=4817879251025920

Fuzzer: bcrane-css-mutator
Job Type: linux_ubsan_vptr_content_shell_drt
Platform Id: linux

Crash Type: CHECK failure
Crash Address: 
Crash State:
  delegate in gamepad_controller.cc
  test_runner::GamepadController::Create
  test_runner::TestInterfaces::SetDelegate
  
Sanitizer: undefined (UBSAN)

Regressed: https://cluster-fuzz.appspot.com/revisions?job=linux_ubsan_vptr_content_shell_drt&range=454833:454835
Fixed: https://cluster-fuzz.appspot.com/revisions?job=linux_ubsan_vptr_content_shell_drt&range=454873:455052

Reproducer Testcase: https://cluster-fuzz.appspot.com/download/AMIfv97oLNA2n0vkCEnpwIcYEQv46RWoNbqZfnAQKYiuPO1Ncf_DPHIgT-D2QtEw0p35D5wTXVvfRhQgMiUn9H3Gh-3p9rlAXuI2bFrFBCGfMA-3_3Dv4SepoOqBa6VzhjAeK0Sj_f2NXBsTPjtgOGjWmiKko9DbN6-QnUGgmdxZf1dXc5RfAby-gHCu7VqRXj4d9zF2Ge-QIoZ7rXamyIr6UcMhUEeS-SV04qLiZJuImFdQWP3eJ5IDD3t2YWXrQZkqNmVyN5Mr_jZxo0lDcMPmNKvCzUXICvxv7qzrOEQvPuTxdmPYezhxKLkm9t6zrqO4aXaO1lYZy42aehoRCOXFzCIQkNPC1xdl-lduxWUUAx7Zt3EgQ_Q?testcase_id=4817879251025920


See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.