Add some factory boilerplate needed for sync in //ios/web_view.

//ios/web_view will use sync for autofill and password data in the
near future. This is one of the many CLs needed for implementation.

Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I32c84aa7d5fd1836a99170741f525100dc0ac09c
Reviewed-on: https://chromium-review.googlesource.com/1139182
Commit-Queue: John Wu <jzw@chromium.org>
Reviewed-by: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Reviewed-by: Hiroshi Ichikawa <ichikawa@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576194}
7 files changed