Also fixes #18687.

Change-Id: I7c6d47c71e632adf4c16937a29074621f771844c
Reviewed-on: https://go-review.googlesource.com/35261
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>