Revert of revert as the new changes that use nullptr in fold function
are already in.

This reverts commit b775778a.

Change-Id: Ifbdb35264132c66e5d1f2379932839b99291c54a
Reviewed-on: https://chromium-review.googlesource.com/266803Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>