The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/51c1d401e175c9005be2bd7b8eafac05b705c764

commit 51c1d401e175c9005be2bd7b8eafac05b705c764
Author: Robert Ma <robertma@chromium.org>
Date: Thu Apr 12 14:02:47 2018

Add test expectations for some new tests that cannot be rebaselined

The tests have unstable failure messages. Add these expectations in
advance to unblock wpt-importer.

TBR=kereliuk

No-Try: True
Bug: 832071
Change-Id: I4a1efcd869f3660f4a88d37e9a02bf4bc9f0ee40
Reviewed-on: https://chromium-review.googlesource.com/1010243
Commit-Queue: Robert Ma <robertma@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550178}
[modify] https://crrev.com/51c1d401e175c9005be2bd7b8eafac05b705c764/third_party/WebKit/LayoutTests/TestExpectations

I wrote this test.  We can change it to not include transient data like this.  I'll make a note about the problem for future test write.  Sorry for the trouble.

Thanks, bkelly@! Once you changed the test, could you give us a heads up so that we can rebaseline it?

bkelly thanks a lot for the offer but I think it's fine to leave it as is... It's Chrome's fault we're failing this test, and assert_not_equals(id1, id2) is a natural way to the write the test...

robertma thanks for adding the lines in TestExpectations.

Hi, I did some investigation on this issue, and found the client id was originally created during construction of ServiceWorkerProviderHost. 

And it seems a bit strange that the ServiceWorkerProviderType doesn't include Dedicated Worker. While according to the spec (https://w3c.github.io/ServiceWorker/#service-worker-client-concept), dedicated worker is also a client type. So I'm wondering is it missed or there are some other considerations. Thanks.

Thanks for looking into this. Yes, dedicated workers are not yet supported as service worker clients, and when a "controlled" dedicated worker does a fetch() we reuse the client id of its ancestor frame, so this WPT will fail for a while. We will be able to fix it after "PlzWorker" work ongoing for  issue 715632 .

Thanks falken for the explanation.