Register a pref to control migration status
Domain scoped content settings are migrated to be origin scoped, but the
migration process is expected to run only once. In this CL, a pref is registered
to control this, which has three states:
1. not migrated, which means the migration process has not been started yet.
2. migrated in HostContentSettingsMap(HCSM), which will not do migration again
in HCSM, but can do in PrefModelAssociator.
3. migrated in PrefModelAssociator, which means the migration is all finished
and won't get called again.
BUG=604612
Review-Url: https://codereview.chromium.org/2158743002
Cr-Commit-Position: refs/heads/master@{#408064}
5 files changed
