SigninManager owns ObserverList for the MergeSessionHelper.

SigninManager owns ObserverList for the MergeSessionHelper.

BUG=458903
TEST=You can sign into chrome, and your signin credential also gets
pushed into the cookie jar (for gmail). Also, if you re-auth in the
browser after changing your password, your signin credential for the
content area still also (still) gets updated.

Committed: https://crrev.com/2ce480a20c0487af08240bd03865f824d38edd2c
Cr-Commit-Position: refs/heads/master@{#316606}

[Mike Lerman, 2015-02-17 16:25:28]

mlerman@chromium.org changed reviewers:
+ rogerta@chromium.org

[Mike Lerman, 2015-02-17 16:25:29]

Hi Roger,

Here's the fix for the issue around the MergeSessionHelper observing we discuss
this morning. Thanks,
Mike

[Roger Tawa OOO till Jul 10th, 2015-02-17 16:50:31]

lgtm

[Mike Lerman, 2015-02-17 17:30:54]

The CQ bit was checked by mlerman@chromium.org

[commit-bot: I haz the power, 2015-02-17 17:32:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/936503002/20001

[commit-bot: I haz the power, 2015-02-17 18:04:21]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-17 18:04:45]

Patchset 2 (id:??) landed as
https://crrev.com/2ce480a20c0487af08240bd03865f824d38edd2c
Cr-Commit-Position: refs/heads/master@{#316606}