Forked from CL 111895.

For #11799.

Change-Id: Ie1346ac2c9122de494823b9058df3a0971e9dfe1
Reviewed-on: https://go-review.googlesource.com/118277
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>