Fixes #16681

Change-Id: I6ff7ec81fe48ab06be3aae5b7ff92e9dc70960c3
Reviewed-on: https://go-review.googlesource.com/26990
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>