Move preference MACs to the protected preference stores.
(1) 1-time migration of MACs from local state to Preferences/Protected Preferences.
(2) Migrate MACs between Preferences/Protected Preferences according to configuration changes.
Proposed follow-up tasks are:
(1) Introduce TrackedPreferencesMigrationDelegate
(2) Introduce protections to prevent unintended stamping of the super MAC.
(3) Expanded test coverage of PrefHashFilter
(4) Expanded test coverage for legacy migration in TrackedPreferencesMigrationTest
BUG=372547, 368480
R=asvitkine@chromium.org, gab@chromium.org
Review URL: https://codereview.chromium.org/324493002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278164 0039d316-1c4b-4281-b951-d872f2087c98
CrOS-Libchrome-Original-Commit: 1b5837665d4a213c8f18b4c70fe3feb2117ce744
6 files changed