Background: for some time, the layout test runner was not treating testharness.js tests with "harness errors" as failures ( bug 703331 ), and so no -expected.txt file was kept since all of the tests appeared to PASS.
After making "harness errors" count as failures, an -expected.txt would have to be kept, but can only be kept if the expected result is deterministic.
This is a tracking bug for tests that fail with harness errors and also don't have deterministic results.
Comment 1 by bugdroid1@chromium.org
, Mar 27 2017