cros: Fix MD OOBE crash

cros: Fix MD OOBE crash

Reset |oobe_ui_| in ShowLoginScreen is legacy code back when there
are separate OobeDisplay and LoginDisplay. OobeDisplay is no longer
needed when login screen is shown. This has changed as there is
only one LoginDisplay and |oobe_ui_| is used for both OOBE and login.
And it should not change during the lifetime of WizardController.

BUG=647742
Committed: https://crrev.com/14947f5240be7a4263819e4d80cf3bef350f51d0
Cr-Commit-Position: refs/heads/master@{#419308}

[xiyuan, 2016-09-16 21:42:45]

xiyuan@chromium.org changed reviewers:
+ jdufault@chromium.org

[xiyuan, 2016-09-16 21:42:55]

The CQ bit was checked by xiyuan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-16 21:43:29]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[jdufault, 2016-09-16 21:46:53]

lgtm

[commit-bot: I haz the power, 2016-09-16 22:25:46]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-16 22:25:47]

Dry run: This issue passed the CQ dry run.

[xiyuan, 2016-09-16 22:28:15]

The CQ bit was checked by xiyuan@chromium.org

[commit-bot: I haz the power, 2016-09-16 22:28:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-16 22:36:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-16 22:39:34]

Description was changed from

==========
cros: Fix MD OOBE crash

Reset |oobe_ui_| in ShowLoginScreen is legacy code back when there
are separate OobeDisplay and LoginDisplay. OobeDisplay is no longer
needed when login screen is shown. This has changed as there is
only one LoginDisplay and |oobe_ui_| is used for both OOBE and login.
And it should not change during the lifetime of WizardController.

BUG=647742
==========

to

==========
cros: Fix MD OOBE crash

Reset |oobe_ui_| in ShowLoginScreen is legacy code back when there
are separate OobeDisplay and LoginDisplay. OobeDisplay is no longer
needed when login screen is shown. This has changed as there is
only one LoginDisplay and |oobe_ui_| is used for both OOBE and login.
And it should not change during the lifetime of WizardController.

BUG=647742

Committed: https://crrev.com/14947f5240be7a4263819e4d80cf3bef350f51d0
Cr-Commit-Position: refs/heads/master@{#419308}
==========

[commit-bot: I haz the power, 2016-09-16 22:39:34]

Patchset 1 (id:??) landed as
https://crrev.com/14947f5240be7a4263819e4d80cf3bef350f51d0
Cr-Commit-Position: refs/heads/master@{#419308}