Just moving code. No code changes.

Updates #15345

Change-Id: I89c257b7aae4fbd78ce59a42909ecb3ff493659d
Reviewed-on: https://go-review.googlesource.com/22300Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>