Fix GN bootstrap BUG=none R=dpranke@chromium.org Review URL: https://codereview.chromium.org/2198023002 . Cr-Original-Commit-Position: refs/heads/master@{#409158} Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src Cr-Mirrored-Commit: c0854701a20853eb16cf4aa7a9584eefa000d559