The implementation can be greatly simplified by using variadic
templates.

R=mstarzinger@chromium.org

Change-Id: I8dbeea3d570bf0fac83109f334c48dbe39aaa853
Reviewed-on: https://chromium-review.googlesource.com/859785
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50611}