GitLab

Use Chromium pref as a persistant key-value storage to save previously
used transport type. This will enable us to skip "Welcome" dialog if we
know that the user has already used certain transport type before.

Bug: 868212
Change-Id: Iff732f2d990291cfe1465107fc01d08b3cf3e019
Reviewed-on: https://chromium-review.googlesource.com/1152559
Commit-Queue: Jun Choi <hongjunchoi@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Kim Paulhamus <kpaulhamus@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580028}