Load policy before signin completes.

Updated SigninManager to call into UserPolicySigninService to register for policy and fetch policy as appropriate.

Refactored UserPolicySigninService to expose an external API to register for policy.

BUG=160922

Review URL: https://codereview.chromium.org/12220060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@181492 0039d316-1c4b-4281-b951-d872f2087c98
11 files changed