Update GN bootstrap to reflect the latest changes in //base.

TBR=brettw@chromium.org

Review-Url: https://codereview.chromium.org/2416853004
Cr-Original-Commit-Position: refs/heads/master@{#425169}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9ed58da93e8cae421d5cdf37addfa1ec471431c8