Fixes #20014

Change-Id: Ie58d3e989f2d7388b3d8849fbcfbceed3c6aa084
Reviewed-on: https://go-review.googlesource.com/41132
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>