This removes the static helper which is by now only used by a single
runtime function. In general the {Runtime} class no longer acts as a
grab-bag for various helper functions.

R=petermarshall@chromium.org

Change-Id: I9c2141bbd88db27ae1f95fe004bcc8a7c5506208
Reviewed-on: https://chromium-review.googlesource.com/459597
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44174}