Revert of Delete dead signin code (SigninGlobalError)

Revert of Delete dead signin code (SigninGlobalError) (patchset #8 id:140001 of https://codereview.chromium.org/1299543002/ )

Reason for revert:
Broke the Mac10.9 Tests (dbg) bot:

http://build.chromium.org/p/chromium.mac/builders/Mac10.9%20Tests%20%28dbg%29/builds/10278

See the stack trace in the logs.

Original issue's description:
> Delete dead signin code (SigninGlobalError)
>
> BUG=none
>
> Committed: https://crrev.com/c91b178b07b0d9fb0c7a437df3a1da3db1887160
> Cr-Commit-Position: refs/heads/master@{#344176}

TBR=anthonyvd@chromium.org,sky@chromium.org,rogerta@chromium.org,estade@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=none

Committed: https://crrev.com/7529916efbda5763f6b5ddd9256ea46e29065281
Cr-Commit-Position: refs/heads/master@{#344188}

[Adam Rice, 2015-08-19 09:30:49]

Created Revert of Delete dead signin code (SigninGlobalError)

[commit-bot: I haz the power, 2015-08-19 09:31:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1301583004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1301583004/1

[commit-bot: I haz the power, 2015-08-19 09:32:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-19 09:32:44]

Patchset 1 (id:??) landed as
https://crrev.com/7529916efbda5763f6b5ddd9256ea46e29065281
Cr-Commit-Position: refs/heads/master@{#344188}