GitLab

This CL replaces some uses of the non-existent
--google-grey-600 with --paper-grey-600

BUG=589630
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2010283003
Cr-Commit-Position: refs/heads/master@{#398150}