Refactor sequence_manager_impl_unittest.cc

Cleanup final bits of custom initialization tests.

Bug: 891670
Change-Id: I72c5dc8699831a9b92254770a414b7a137adaa82
Reviewed-on: https://chromium-review.googlesource.com/c/1473232
Commit-Queue: Carlos Caballero <carlscab@google.com>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632608}
1 file changed