Add SigninManager::TransferCredentialsToNewProfile() API.

This API is not yet called pending the addition of associated UI.

TBR=erg

BUG=171236


Review URL: https://chromiumcodereview.appspot.com/12210089

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@181567 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed