Show DRP promo on second run

The promo is currently being shown on second run because native
initialization can finish before the FRE completes. Therefore the
PROMOS_SKIPPED_ON_FIRST_START pref isn't set until the second run,
and then the promo is shown on the third.

BUG=672954

Review-Url: https://codereview.chromium.org/2824893002
Cr-Commit-Position: refs/heads/master@{#465085}
1 file changed