This is a testharness.js-based test.
[FAIL] Default view-timeline
  assert_equals: expected "100" but got "-1"
[FAIL] Horizontal view-timeline
  assert_equals: expected "100" but got "-1"
[FAIL] Multiple view-timelines on the same element
  assert_equals: expected "100" but got "-1"
Harness: the test ran to completion.