It was not responsive to the sizes param.
Remove it, and unwind the extra layers.

Fixes #16316

Change-Id: I940a57184a1601f52348d4bff8638f3f7462f5cd
Reviewed-on: https://go-review.googlesource.com/26995
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>