Updates #17057.

Change-Id: I54c838d3a44007d4023754e42971e91bfb5e8612
Reviewed-on: https://go-review.googlesource.com/32851
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>