arc: Show migration success notification on the next sign-in after migration.

arc: Show migration success notification on the next sign-in after migration.

Referring the tri-state preference, shows the notification when needed.
The special case is when the profile was newly created on the device.
In that case, the profile is on the compatible filesystem from the beginning,
we skip showing the migration and mark the pref as if it has been shown.

BUG=711095
TEST=Manually tried new/migrated/skipped-migration/guest/supervised accounts.

Review-Url: https://codereview.chromium.org/2828213002
Cr-Commit-Position: refs/heads/master@{#466592}
(cherry picked from commit c6d7406702779c75f188e7380dd71f211ed4e765)

Review-Url: https://codereview.chromium.org/2840203002 .
Cr-Commit-Position: refs/branch-heads/3071@{#223}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/9ad42d0a1f85ca03d84eb5ae8f9d8743c32f2c05

[kinaba, 2017-04-26 11:50:06]

Description was changed from

==========
arc: Show migration success notification on the next sign-in after migration.

Referring the tri-state preference, shows the notification when needed.
The special case is when the profile was newly created on the device.
In that case, the profile is on the compatible filesystem from the beginning,
we skip showing the migration and mark the pref as if it has been shown.

BUG=711095
TEST=Manually tried new/migrated/skipped-migration/guest/supervised accounts.

Review-Url: https://codereview.chromium.org/2828213002
Cr-Commit-Position: refs/heads/master@{#466592}
(cherry picked from commit c6d7406702779c75f188e7380dd71f211ed4e765)
==========

to

==========
arc: Show migration success notification on the next sign-in after migration.

Referring the tri-state preference, shows the notification when needed.
The special case is when the profile was newly created on the device.
In that case, the profile is on the compatible filesystem from the beginning,
we skip showing the migration and mark the pref as if it has been shown.

BUG=711095
TEST=Manually tried new/migrated/skipped-migration/guest/supervised accounts.

Review-Url: https://codereview.chromium.org/2828213002
Cr-Commit-Position: refs/heads/master@{#466592}
(cherry picked from commit c6d7406702779c75f188e7380dd71f211ed4e765)

Review-Url: https://codereview.chromium.org/2840203002 .
Cr-Commit-Position: refs/branch-heads/3071@{#223}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/9ad42d0a1f85ca03d84eb5ae8f9d...
==========

[kinaba, 2017-04-26 11:50:09]

Committed patchset #1 (id:1) manually as
9ad42d0a1f85ca03d84eb5ae8f9d8743c32f2c05.