GitLab

Now we are using AttestationClient directly instead of passing through
CryptohomeClient.

BUG=b:158955123
TEST=build ok.

Change-Id: I38e0cb370cfeb93a4388d62c09040faf4203af58
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2467639
Commit-Queue: Leo Lai <cylai@google.com>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821628}