Renamed persistent tab restore service.

In preparation for another CL which makes persitence dependent on a policy pref.

Bug: 869580
Change-Id: I5fa64297c9c6dbddf121703686c41f1a52bae1d8
Reviewed-on: https://chromium-review.googlesource.com/c/1378229
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Marc-André Decoste <mad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616733}
12 files changed