Fixed notification time of SignInStateObserver.onSignedOut().

Fixed notification time of SignInStateObserver.onSignedOut().

When a managed account signs out then there is a progress dialog while
the profile data is being wiped. Any pending observers should only be
notified that a sign out has completed once this process is done.

This fixes a crash in the SigninTests because the ProgressDialog
isn't getting properly dismissed before the test ends.

BUG=436068
Committed: https://crrev.com/be4481d5b7e925c4cf9af2b6d02a70fea43463b9
Cr-Commit-Position: refs/heads/master@{#306662}

[Joao da Silva, 2014-12-03 19:33:31]

joaodasilva@chromium.org changed reviewers:
+ nyquist@chromium.org

[Joao da Silva, 2014-12-03 19:33:32]

Please see also the downstream fix at
https://chrome-internal-review.googlesource.com/#/c/186756.

@Tommy: PTAL

@Anthony FYI

Thanks!

[nyquist, 2014-12-03 19:37:34]

lgtm, thanks!

[Joao da Silva, 2014-12-03 19:43:25]

The CQ bit was checked by joaodasilva@chromium.org

[commit-bot: I haz the power, 2014-12-03 19:44:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/777733002/1

[commit-bot: I haz the power, 2014-12-03 20:22:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-03 20:23:05]

Patchset 1 (id:??) landed as
https://crrev.com/be4481d5b7e925c4cf9af2b6d02a70fea43463b9
Cr-Commit-Position: refs/heads/master@{#306662}