Updates #16360.

Change-Id: I75714d2b5f095fe39fd81edfa6dd9e44d7c44da1
Reviewed-on: https://go-review.googlesource.com/29375
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>