GitLab

Instead of passing BucketMapper as a raw pointer and then taking
ownership by wrapping it in a unique_ptr, pass it in as a unique_ptr
directly.

Bug: None
Change-Id: I3357fe432651c9dcd7884d6f6d7e76040c70d806
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2015631Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734591}