[Sheriff] Fix gn build.
[Sheriff] Fix gn build.

TBR=jochen@chromium.org, rmcilroy@chromium.org, hablich@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1234573003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29637}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh