cros: Remove ash::Shell access from first-run webui handler
The old code was reaching into ash to get the shelf alignment. This
won't work with out-of-process ash (see //ash/README.md). Convert to
using ash/public/cpp and profile pref.
This enables the first run browser_tests under mash.
Bug: 770866, 756057
Test: browser_tests --enable-features=Mash
Change-Id: I43b202ef255301f637593e24a588a42bacdc7fff
Reviewed-on: https://chromium-review.googlesource.com/1022523
Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#552499}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9a795ad4744d54ebad122411d6ce5e15a44718611 file changed
