GitLab

Allow TpmChallengeKeySubtle to be instantiated with a nullptr Profile*.
Such an instance can only be used to work with machine keys (device-wide
keys).
This is useful to decouple the device-wide CertProvisioningScheduler
from the sign-in Profile.

Bug: 1045895
Change-Id: I42382d3be03aa371d4ba31aaebb2891326e24599
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2189650
Commit-Queue: Pavol Marko <pmarko@chromium.org>
Reviewed-by: Michael Ershov <miersh@google.com>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790540}