Encountered this in
https://chromium-review.googlesource.com/c/chromium/src/+/840142/1

Couple more failures:
https://ci.chromium.org/buildbot/tryserver.chromium.android/android_n5x_swarming_rel/330683
https://ci.chromium.org/buildbot/tryserver.chromium.android/android_n5x_swarming_rel/330633

Log:
I  483.301s run_tests_on_device(01e27ce90bd99839)  [ RUN      ] AccessibilityHitTestingBrowserTest.HitTestingInIframes
I  483.301s run_tests_on_device(01e27ce90bd99839)  [WARNING:dns_config_service_posix.cc(341)] Failed to read DnsConfig.
I  483.302s run_tests_on_device(01e27ce90bd99839)  [ERROR:devtools_http_handler.cc(249)] Cannot start http server for devtools. Stop devtools.
I  483.302s run_tests_on_device(01e27ce90bd99839)  [WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file assets/snapshot_blob_32.bin
I  483.302s run_tests_on_device(01e27ce90bd99839)  [WARNING:simple_synchronous_entry.cc(1170)] Could not open platform files for entry.
I  483.302s run_tests_on_device(01e27ce90bd99839)  referenceTable head length=54 1
I  483.302s run_tests_on_device(01e27ce90bd99839)  ../../content/browser/accessibility/hit_testing_browsertest.cc:153: Failure
I  483.302s run_tests_on_device(01e27ce90bd99839)  Expected equality of these values:
I  483.302s run_tests_on_device(01e27ce90bd99839)    ui::AX_ROLE_GENERIC_CONTAINER
I  483.302s run_tests_on_device(01e27ce90bd99839)      Which is: 44
I  483.302s run_tests_on_device(01e27ce90bd99839)    hit_node->GetRole()
I  483.302s run_tests_on_device(01e27ce90bd99839)      Which is: 90
I  483.302s run_tests_on_device(01e27ce90bd99839)  [  FAILED  ] AccessibilityHitTestingBrowserTest.HitTestingInIframes, where TypeParam =  and GetParam() =  (850 ms)

dmazzoni@, please triage