Updates #17821

Change-Id: Iebd2e88b2d4f3d757ffad72456f4bfc0607d8110
Reviewed-on: https://go-review.googlesource.com/33162
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>