cros: Stop showing migration UI in some conditions where users can't start ARC.

cros: Stop showing migration UI in some conditions where users can't start ARC.

In following cases, we don't need to force dircrypto since ARC can not run.
Let's not show the migration UI in such cases.

1) When a user is logging in to the account to add an supervised user.
2) When a user is logging in as a secondary user in multi-profile sessoin.

These conditions do not affect the banners on user pods.

BUG=721622, 721623
TEST=manually tested the cases listed in the CL description.

Review-Url: https://codereview.chromium.org/2877943002
Cr-Original-Commit-Position: refs/heads/master@{#471658}
Review-Url: https://codereview.chromium.org/2884203002 .
Cr-Commit-Position: refs/branch-heads/3071@{#577}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/93ece3922ada41c1f763201d8b8e1a04cd40c3af

[fukino, 2017-05-16 08:58:15]

Description was changed from

==========
cros: Stop showing migration UI in some conditions where users can't start ARC.

In following cases, we don't need to force dircrypto since ARC can not run.
Let's not show the migration UI in such cases.

1) When a user is logging in to the account to add an supervised user.
2) When a user is logging in as a secondary user in multi-profile sessoin.

These conditions do not affect the banners on user pods.

BUG=721622,721623
TEST=manually tested the cases listed in the CL description.

Review-Url: https://codereview.chromium.org/2877943002
Cr-Commit-Position: refs/heads/master@{#471658}
(cherry picked from commit 77f5935267dfb3f96b9194b18e9b824ba086ea74)
==========

to

==========
cros: Stop showing migration UI in some conditions where users can't start ARC.

In following cases, we don't need to force dircrypto since ARC can not run.
Let's not show the migration UI in such cases.

1) When a user is logging in to the account to add an supervised user.
2) When a user is logging in as a secondary user in multi-profile sessoin.

These conditions do not affect the banners on user pods.

BUG=721622,721623
TEST=manually tested the cases listed in the CL description.

Review-Url: https://codereview.chromium.org/2877943002
Cr-Original-Commit-Position: refs/heads/master@{#471658}
Review-Url: https://codereview.chromium.org/2884203002 .
Cr-Commit-Position: refs/branch-heads/3071@{#577}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/93ece3922ada41c1f763201d8b8e...
==========

[fukino, 2017-05-16 08:58:17]

Committed patchset #1 (id:1) manually as
93ece3922ada41c1f763201d8b8e1a04cd40c3af.