GitLab

Move mergesession from SigninManager to reconcilor.
Implement ListAccounts.
Start implementing reconcile action, but still a noop for now.

This CL depends on https://codereview.chromium.org/57103002/

Alan: here is an implementation of the ListAccounts.  I also added lots of
DVLOG() to the code.  Let me know if you'd rather I took those out and put
in a separate CL.

Hui: please review.  This CL adds more functionality to the reconcilor but
its still not complete.  However, it enables AC behind the flag for merge
session so you don't need to do that manually.

BUG=305249

Review URL: https://codereview.chromium.org/57363003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233424 0039d316-1c4b-4281-b951-d872f2087c98