Forgot to do this for golang.org/cl/76312.

Change-Id: Ic20fef3eeff14a805f608221aff1fa03934be3ca
Reviewed-on: https://go-review.googlesource.com/c/141357
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>