Gardening: NetworkService: add expectation for fetch-event.https.html.

The non-S13nServiceWorker path started passing after bug 807818 was
fixed, so the S13nServiceWorker path started failing since clientId
isn't implemented there.

TBR=bashi, shimazu

Bug: 807818,780405
NOTRY: true
Change-Id: I3055b18262e3acd3095227db06b2fa9a67f53564
Reviewed-on: https://chromium-review.googlesource.com/897072Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533658}

third_party/WebKit/LayoutTests/flag-specific/enable-features=NetworkService/external/wpt/service-workers/service-worker/fetch-event.https-expected.txt

+This is a testharness.js-based test.
+PASS Service Worker headers in the request of a fetch event
+PASS Service Worker responds to fetch event with string
+PASS Service Worker responds to fetch event with blob body
+PASS Service Worker responds to fetch event with the referrer URL
+FAIL Service Worker responds to fetch event with an existing client id assert_unreached: unexpected rejection: assert_equals: Service Worker should respond to fetch with an existing client id expected "Client ID Found" but got "Client ID Not F" Reached unreachable code
+PASS Service Worker does not respond to fetch event
+PASS Service Worker responds to fetch event with null response body
+PASS Service Worker fetches other file in fetch event
+PASS Service Worker responds to fetch event with POST form
+PASS Service Worker falls back to network in fetch event with POST form
+PASS Multiple calls of respondWith must throw InvalidStateErrors
+PASS Service Worker event.respondWith must set the used flag
+PASS Service Worker should expose FetchEvent URL fragments.
+PASS Service Worker responds to fetch event with the correct cache types
+PASS Service Worker should intercept EventSource
+FAIL Service Worker responds to fetch event with the correct integrity_metadata assert_unreached: unexpected rejection: assert_equals: integrity expected "gs0nqru8KbsrIt5YToQqS9fYao4GQJXtcId610g7cCU=" but got "" Reached unreachable code
+PASS FetchEvent#body is a string
+PASS FetchEvent#body is a string and is passed to network fallback
+PASS FetchEvent#body is a blob
+PASS FetchEvent#body is a blob and is passed to network fallback
+PASS Service Worker responds to fetch event with the correct keepalive value
+Harness: the test ran to completion.
+