Fixes #16884
Updates #16360

Change-Id: I01563031a1c105e54499134eed4789f6219f41ec
Reviewed-on: https://go-review.googlesource.com/27993Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>