One of the early (no-op) returns forgot to check whether the
number of existing digits equals the number of required digits.

Bug: chromium:936506
Change-Id: Ic9a5b927306de3cd6b26662785ac11d866e12026
Reviewed-on: https://chromium-review.googlesource.com/c/1493133Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59929}