This failure is triggered by running the test with the --enable-features=NetworkService flag, as is done on the Mojo Linux FYI bot.

Output is:

01:59:57.198 11667 Starting 1 worker ...
01:59:57.198 11667 worker/0 starting
01:59:59.247 11667 worker/0 virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/fetch-event.https.html output stderr lines:
01:59:59.247 11667   
01:59:59.247 11667   DevTools listening on ws://127.0.0.1:33197/devtools/browser/2bcf0287-3911-4d37-8631-09ef7ec88559
01:59:59.247 11667   Fontconfig warning: "/etc/fonts/fonts.conf", line 146: blank doesn't take any effect anymore. please remove it from your fonts.conf
01:59:59.247 11667   CONSOLE ERROR: Error parsing 'integrity' attribute ('gs0nqru8KbsrIt5YToQqS9fYao4GQJXtcId610g7cCU='). The hash algorithm must be one of 'sha256', 'sha384', or 'sha512', followed by a '-' character.
01:59:59.248 11667 [1/1] virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/fetch-event.https.html failed unexpectedly (text diff)

Thanks! I am taking a look.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e1208febc77b27c8b28296be2e2a71f52cbeac38

commit e1208febc77b27c8b28296be2e2a71f52cbeac38
Author: Reilly Grant <reillyg@chromium.org>
Date: Thu Feb 08 15:30:25 2018

Add expectations for LayoutTest failing with Network Service

virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/fetch-event.https.html
is failing consistency when the network service flag is enabled.

TBR=arthursonzogni@chromium.org

Bug:  810394 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Ib416411f23df2845d4ee1e19174f726560f4fa6a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/908829
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535387}
[modify] https://crrev.com/e1208febc77b27c8b28296be2e2a71f52cbeac38/third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService

I try reverting my patch, this ServiceWorker test still not work with both NavigationMojoResponse && NetworkService enabled at the same time.

That's strange. I expect (NavigationMojoResponse && NetworkService) to work exactly the same as (NetworkService) alone.

I will continue investigating...

+CC people that may be interested. FYI.

I don't think you need to revert. Hold on.

I reverted locally of course ;-) to see if I broke something with my previous patch. That is not the case.

This test was not working before and after this patch.

This is expected because the test is already failing with NetworkService, but it has an -expected.txt file:
https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/flag-specific/enable-features%3DNetworkService/external/wpt/service-workers/service-worker/fetch-event.https-expected.txt

I think you just need to add the same file to
https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/flag-specific/enable-features%3DNetworkService/virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/fetch-event.https-expected.txt

But note that bashi@ has a patch that will fix the test anyway:
https://chromium-review.googlesource.com/c/chromium/src/+/897041

Thanks!

I only look for: third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService
I didn't know there was such a directory like third_party/WebKit/LayoutTests/flag-specific/enable-features=NetworkService/

I will do what you said.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6cd234cccefd6f73024ba831877a06d8f2ab873e

commit 6cd234cccefd6f73024ba831877a06d8f2ab873e
Author: arthursonzogni <arthursonzogni@chromium.org>
Date: Fri Feb 09 10:04:03 2018

Add expectations for LayoutTest failing with Network Service.

This test is failing with the NetworkService,
enabling NavigationMojoResponse or not doesn't matter.

TBR=reillyg@chromium.org

Bug:  810394 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I38b4f1fa1e9794415df128d23f3d08fffd6ae4d9
Reviewed-on: https://chromium-review.googlesource.com/909208
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535678}
[modify] https://crrev.com/6cd234cccefd6f73024ba831877a06d8f2ab873e/third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService
[add] https://crrev.com/6cd234cccefd6f73024ba831877a06d8f2ab873e/third_party/WebKit/LayoutTests/flag-specific/enable-features=NetworkService/virtual/navigation-mojo-response/external/wpt/service-workers/service-worker/fetch-event.https-expected.txt