Updates #29983

Change-Id: Ifdf8aa9c92e053374e301a4268d85e277c15f0b5
Reviewed-on: https://go-review.googlesource.com/c/160182
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>