update-top-level.https.html was added by https://github.com/web-platform-tests/wpt/pull/12633.

I don't see why we'd time out on this test though.

I think it's a problem with the WPT test. I commented on https://bugzilla.mozilla.org/show_bug.cgi?id=1472303#c11:

The update() call is failing with an InvalidStateError. I think this aligns with the spec at https://w3c.github.io/ServiceWorker/#service-worker-registration-update: if the state is installing, reject the promise with InvalidStateError.

Also I don't think this part is valid:

  reg.addEventListener("updatefound",
    () => assert_unreached("shouldn't find an update"));

The spec says UAs can terminate long running workers, but it would still be spec-conformant to find an update. (Chrome allows some updates before blocking the call.)

I'm not sure how to change this test. We could let the service worker reach active, then give it a message to try self-update, but this bug seems about update at top-level.

I think you'd have to install the service worker once, use some implementation specific way to stop the worker, then start it again.

Not sure WPT would be possible here. Chrome has a similar test for self-updating workers at:
https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/http/tests/serviceworker/update-no-controllee.https.html

The test will be removed in https://github.com/web-platform-tests/wpt/pull/12676

I assume after that WPT importer will either remove the test expectation or we must do it manually, then close this bug. Setting NextAction for that.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e75d0a3a1752b1915e3a5a121e16ad430f125c1d

commit e75d0a3a1752b1915e3a5a121e16ad430f125c1d
Author: Matt Falkenhagen <falken@chromium.org>
Date: Wed Aug 29 04:27:29 2018

Gardening: remove nonexistent update-top-level.https.html from TestExpectations

update-top-level.https.html was removed in r586750.

Bug:  877377 ,  878657 , 626703
Change-Id: I9b64b469a58ad137018893601353097dbdfe21c8
TBR: robertma
NOTRY: true
Reviewed-on: https://chromium-review.googlesource.com/1195227
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587010}
[modify] https://crrev.com/e75d0a3a1752b1915e3a5a121e16ad430f125c1d/third_party/WebKit/LayoutTests/TestExpectations

The test was removed, see  https://bugzilla.mozilla.org/show_bug.cgi?id=1472303

The NextAction date has arrived: 2018-08-29