[login_manager] Add some sanity checks for input from DBus
[login_manager] Add some sanity checks for input from DBus

BUG=None
TEST=manual, with login_drive tool from cros.git

Change-Id: Ieabf034a49b23e6695f32986269b7585409a511f

Review URL: http://codereview.chromium.org/3355005

chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager,joshfire/chromiumos-platform-login_manager,chadversary/chromiumos.platform.login_manager,chadversary/chromiumos.platform.login_manager,joshfire/chromiumos-platform-login_manager