The same overrides now live in .gn.

TBR=kjellander@chromium.org
Bug:chromium:669240
Change-Id: Ifaeb3b612571c3594f1e2279b4f871b7fd3e8d69
Reviewed-on: https://chromium-review.googlesource.com/572080Reviewed-by: Frank Barchard <fbarchard@google.com>