GitLab

No change to logic, this just removes redundant imports to clarify this
class's dependencies.

Bug: 994839
Test: autoninja -C out/Default chrome
Change-Id: I579d9f1b3b24135fa729af3ca063eb3023a2d83e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1828497Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700917}