GitLab

Writes the key to the file, parses it from the file during
initialization. Encryption is controlled by base::FeatureList;
if encryption is enabled, fail Storage initialization.
Later on we will instead send Upload with no records and
only need_encryption_key flag and reject Enqueue until it is
responded.

Bug: b:170054326
Change-Id: I343b17f9363e11b62e6ab1f69148a7e9e8e0d4c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2586086Reviewed-by: Zach Trudo <zatrudo@google.com>
Commit-Queue: Leonid Baraz <lbaraz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836807}