Added base::TimeToISO8601 and deleted all other instances

It is not uncommon to want to convert from base::Time to an
ISO-8601 string so instead of having half a dozen implementations,
it's better to have one implementation.

This was noticed in the jumbo project because two of
the implementations ended up in the same translation unit.

Bug: 746957
Change-Id: Ib88832c53930aff7a6c24a0df81afc28cbbecc35
Reviewed-on: https://chromium-review.googlesource.com/895456
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#535691}
9 files changed