cros: Add UMA metrics in migration UI to get more information from migration failures.

cros: Add UMA metrics in migration UI to get more information from migration failures.

To get more information about migration failures from UMA stats, I'd like to add/update following histograms.

1) Cryptohome.MigrationUI.MigrationResult (new)
We'd like to know the migration result, including errors which only Chrome knows (i.e. Chrome failed to mount existing vault)

2) Cryptohome.MigrationUI.RemoveCryptohomeResult (new)
Chrome UI code tries to remove the user's cryptohome when migration fails.
We'd like to know if the removal succeeds, which we don't have information before.

3) Cryptohome.MigrationUI.VisibleScreen (new)
In theory, a screen can be displayed as a flash (especially in shutdown sequence). We'd like to know how many times each screen *actually* gets visible to users. (i.e. displayed at least 1 second.)

4) Cryptohome.MigrationUI.UserChoice (expansion on existing one)
We have recorded click events on "Update" and "Skip" button on the migration UI. We'd like to know about other buttons such as "Restart" on error screen, too.

BUG=726213
TEST=checked chrome://histograms by disabling auto restart after migration.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2910423002
Cr-Original-Commit-Position: refs/heads/master@{#476592}
Review-Url: https://codereview.chromium.org/2917303002 .
Cr-Commit-Position: refs/branch-heads/3112@{#139}
Cr-Branched-From: b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed: https://chromium.googlesource.com/chromium/src/+/eca63e9f4523341a3d46b4e0c515d8b3c17c092e

[fukino, 2017-06-05 03:27:08]

Description was changed from

==========
cros: Add UMA metrics in migration UI to get more information from migration
failures.

To get more information about migration failures from UMA stats, I'd like to
add/update following histograms.

1) Cryptohome.MigrationUI.MigrationResult (new)
We'd like to know the migration result, including errors which only Chrome knows
(i.e. Chrome failed to mount existing vault)

2) Cryptohome.MigrationUI.RemoveCryptohomeResult (new)
Chrome UI code tries to remove the user's cryptohome when migration fails.
We'd like to know if the removal succeeds, which we don't have information
before.

3) Cryptohome.MigrationUI.VisibleScreen (new)
In theory, a screen can be displayed as a flash (especially in shutdown
sequence). We'd like to know how many times each screen *actually* gets visible
to users. (i.e. displayed at least 1 second.)

4) Cryptohome.MigrationUI.UserChoice (expansion on existing one)
We have recorded click events on "Update" and "Skip" button on the migration UI.
We'd like to know about other buttons such as "Restart" on error screen, too.

BUG=726213
TEST=checked chrome://histograms by disabling auto restart after migration.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2910423002
Cr-Commit-Position: refs/heads/master@{#476592}
(cherry picked from commit 4e58ceae8e2e76c9f95b835827b588b4da3810f4)
==========

to

==========
cros: Add UMA metrics in migration UI to get more information from migration
failures.

To get more information about migration failures from UMA stats, I'd like to
add/update following histograms.

1) Cryptohome.MigrationUI.MigrationResult (new)
We'd like to know the migration result, including errors which only Chrome knows
(i.e. Chrome failed to mount existing vault)

2) Cryptohome.MigrationUI.RemoveCryptohomeResult (new)
Chrome UI code tries to remove the user's cryptohome when migration fails.
We'd like to know if the removal succeeds, which we don't have information
before.

3) Cryptohome.MigrationUI.VisibleScreen (new)
In theory, a screen can be displayed as a flash (especially in shutdown
sequence). We'd like to know how many times each screen *actually* gets visible
to users. (i.e. displayed at least 1 second.)

4) Cryptohome.MigrationUI.UserChoice (expansion on existing one)
We have recorded click events on "Update" and "Skip" button on the migration UI.
We'd like to know about other buttons such as "Restart" on error screen, too.

BUG=726213
TEST=checked chrome://histograms by disabling auto restart after migration.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2910423002
Cr-Original-Commit-Position: refs/heads/master@{#476592}
Review-Url: https://codereview.chromium.org/2917303002 .
Cr-Commit-Position: refs/branch-heads/3112@{#139}
Cr-Branched-From:
b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed:
https://chromium.googlesource.com/chromium/src/+/eca63e9f4523341a3d46b4e0c515...
==========

[fukino, 2017-06-05 03:27:11]

Committed patchset #1 (id:1) manually as
eca63e9f4523341a3d46b4e0c515d8b3c17c092e.