Update #14559.

Change-Id: I92603602e5d0a5fcae43f3084f234ff606447190
Reviewed-on: https://go-review.googlesource.com/20056
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>