Use unique pointers in vectors of current and finished profiles.

Change-Id: Ifb78f7d3804e9883062741fd4e4e31109965d501
Reviewed-on: https://chromium-review.googlesource.com/898984
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51113}