Update #19062.

Change-Id: I7397b573389145b56e73d2150ce0fc9aa75b3caa
Reviewed-on: https://go-review.googlesource.com/36934
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>