GitLab

remove FakeCryptohomeClient from AttestationFlow unittests.

It is not necessary anymore after attestation's GetKeyInfo is used.

BUG=b:158955123
TEST=chromeos_unittests.

Change-Id: I4d288c8de7227b94941da116267a3253f4a71439
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2513950
Commit-Queue: Leo Lai <cylai@google.com>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823884}