Updates #19710

Change-Id: I37d19a4a02b9010cb5f9062b3d141d5d65e12e01
Reviewed-on: https://go-review.googlesource.com/43497
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>