GitLab

SessionServiceTestHelper no longer owns SessionService.
Having SessionServiceTestHelper own the SessionService is
not at all expected and lead to awkward code.

BUG=none
TEST=none

Change-Id: I652de08405d6e66b99ea114cf5c3919042a7e027
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2634221
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: David Bienvenu <davidbienvenu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844886}