GitLab

I'm hoping to use this as a debugging aid for folks that encounter
problems. Specifically I'm planning on creating a page that shows
this information, so that if a user thinks restore should have
happened they can open this page for some diagnostic information.

This is just the persistence part.

BUG=1167296
TEST=SessionServiceLogTest*

Change-Id: I0385c45e4b2913bcf7e601a3caf9c8f26ca15546
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2633072Reviewed-by: David Bienvenu <davidbienvenu@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844288}