Fix ASSERTs on the ChromeOS login screen

This CL suppresses a few more strict state machine asserts. These asserts are
hit only on the Chrome OS login screen. For some reason, that environment is
triggering code paths that don't seem to exist in other configurations. Ideally
we'd figure out how to test this configuration at the Blink layer.

R=ojan@chromium.org

Review URL: https://codereview.chromium.org/161083003

git-svn-id: svn://svn.chromium.org/blink/trunk@167046 bbb929c8-8fbe-4397-9dbb-9b2b20218538