Remove AuthenticationService::GetAuthenticatedUserEmail

Most of the call-sites are only interested whether the user is
authenticated (i.e. they check whether the value returned it not
nil) so convert them to instead use the IsAuthenticatedMethod()

The only call-site that used the returned value can instead be
converted to call GetAuthenticatedIdentity() and use -userEmail

Bug: none
Change-Id: Iac07ad957adef4065cafdf8b681c7677dd674cdd
Commit-Queue: Sylvain Defresne <>
Reviewed-by: David Roger <>
Cr-Commit-Position: refs/heads/master@{#653126}
9 files changed