Fetch: Do not check |integrity| in no-cors mode when constructing a Request

Adapt to https://github.com/whatwg/fetch/pull/584, which removed the check
for |integrity|'s value when constructing a Request in no-cors mode.

Per https://github.com/whatwg/fetch/issues/583: "the issue is that it's
pretty common to do <script integrity="hash"> in your document. This creates
a no-cors request by default. If their service worker script passes through
with fetch(evt.request) then they will get a TypeError."

Note that the external tests added in
https://github.com/w3c/web-platform-tests/commit/96adf8a1a0cdeb70280f0a0e1ef840602c0ce8b0
are still flaky.

Bug: 766975, 766983
Change-Id: I1a787ee39ed94db49ba18f8675edc7dc3019ed26
Reviewed-on: https://chromium-review.googlesource.com/674694
Commit-Queue: Raphael Kubo da Costa (rakuco) <[email protected]>
Reviewed-by: Tsuyoshi Horo <[email protected]>
Reviewed-by: Yutaka Hirano <[email protected]>
Cr-Commit-Position: refs/heads/master@{#503412}
2 files changed