[compute_pressure_detached_iframe.tentative.https.html]
  [PressureObserver.disconnect() on detached frame returns]
    expected: FAIL

  [PressureObserver on detached frame returns with no callback]
    expected: FAIL

  [PressureObserver.observe() on detached frame rejects]
    expected: FAIL

  [Detaching frame while PressureObserver.observe() settles]
    expected: FAIL