GitLab

Use std::unique_ptr instead of deprecated linked_ptr.

BUG=556939

Change-Id: Icf51f7747b2467afe7ffe3995cd7d4e749b31e11
Reviewed-on: https://chromium-review.googlesource.com/578302
Commit-Queue: Xiaofeng Zhang <xiaofeng.zhang@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488587}