[Signin iOS] Ensure SigninInteractionController displays signin errors.

[Signin iOS] Ensure SigninInteractionController displays signin errors.

SigninInteractionController uses an AlertCoordinator to display
potential sign-in errors, which requires the view controler to use to
present the alert dialog.
To ensure SigninInteractionController can always display correctly
errors, the AlertCoordinator must be given the top most visible view
controller (some errors are displayed before the sign-in screen is
shown, and some are displayed on top of the sign-in screen).

BUG=679809
Review-Url: https://codereview.chromium.org/2626003004
Cr-Commit-Position: refs/heads/master@{#443230}
Committed: https://chromium.googlesource.com/chromium/src/+/6f9dd03c83e9a69b48a941b553fe255c68d401d6

[bzanotti, 2017-01-12 14:55:05]

bzanotti@chromium.org changed reviewers:
+ lpromero@chromium.org

[bzanotti, 2017-01-12 14:55:05]

Please take a look.

[lpromero, 2017-01-12 14:57:55]

Description was changed from

==========
[Signin iOS] Ensure SigninInteractionController displays signin errors.

SigninInteractionController uses an AlertCoordinator to display
potential sign-in errors, which requires the view controler to use to
present the alert dialog.
To ensure SigninInteractionController can alway display correctly
errors, the AlertCoordinator must be given the top most visible view
controller (some errors are displayed before the sign-in screen is
shown, and some are displayed on top of the sign-in screen).

BUG=679809
==========

to

==========
[Signin iOS] Ensure SigninInteractionController displays signin errors.

SigninInteractionController uses an AlertCoordinator to display
potential sign-in errors, which requires the view controler to use to
present the alert dialog.
To ensure SigninInteractionController can always display correctly
errors, the AlertCoordinator must be given the top most visible view
controller (some errors are displayed before the sign-in screen is
shown, and some are displayed on top of the sign-in screen).

BUG=679809
==========

[lpromero, 2017-01-12 14:58:16]

The CQ bit was checked by lpromero@chromium.org

[lpromero, 2017-01-12 14:58:16]

lgtm

[commit-bot: I haz the power, 2017-01-12 14:58:29]

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, 2017-01-12 15:10:06]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484233096380050, "parent_rev":
"efd3d8ba87ec8266ab1b5c34cfee31c1121f45ca", "commit_rev":
"6f9dd03c83e9a69b48a941b553fe255c68d401d6"}

[commit-bot: I haz the power, 2017-01-12 15:10:41]

Description was changed from

==========
[Signin iOS] Ensure SigninInteractionController displays signin errors.

SigninInteractionController uses an AlertCoordinator to display
potential sign-in errors, which requires the view controler to use to
present the alert dialog.
To ensure SigninInteractionController can always display correctly
errors, the AlertCoordinator must be given the top most visible view
controller (some errors are displayed before the sign-in screen is
shown, and some are displayed on top of the sign-in screen).

BUG=679809
==========

to

==========
[Signin iOS] Ensure SigninInteractionController displays signin errors.

SigninInteractionController uses an AlertCoordinator to display
potential sign-in errors, which requires the view controler to use to
present the alert dialog.
To ensure SigninInteractionController can always display correctly
errors, the AlertCoordinator must be given the top most visible view
controller (some errors are displayed before the sign-in screen is
shown, and some are displayed on top of the sign-in screen).

BUG=679809

Review-Url: https://codereview.chromium.org/2626003004
Cr-Commit-Position: refs/heads/master@{#443230}
Committed:
https://chromium.googlesource.com/chromium/src/+/6f9dd03c83e9a69b48a941b553fe...
==========

[commit-bot: I haz the power, 2017-01-12 15:10:42]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/6f9dd03c83e9a69b48a941b553fe...