Fix ServiceWorkerTest.MimeHandlerView tests with network service.

The tests check that service workers don't see mimeHandler requests. This still is true with the
network service. However the network service path doesn't copy the subresource_overrides_ field for
ServiceWorkerSubresourceLoaderFactory.

As such, adjust the test to account for 2 by just checking that service workers don't see the mime
handler requests.

Bug: 715640
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I25c473ddd50b7641eb4b3da8883cb9998ad8de4a
Reviewed-on: https://chromium-review.googlesource.com/1056607
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558397}
3 files changed