GitLab

If device was successfully registered with unknown epoch/trusted vault
key, first DownloadKeys call won't have any key available and incoming
keys validation should be skipped.

Note: strictly speaking, there is a constant key; but performing
validation using it doesn't add any value, while would make future
changes harder.

Bug: 1113598
Change-Id: Ib978987b4ba1304f40c54414ea79ef08d7ebb6ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2620262
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842088}