R1:411e16771a25

Make detection/recovery for bad cookies more strict

Summary: When a user has bad cookies, try to clear everything and tell them they
might need to manually clear things.

Test Plan: Added "&& false" to the valid branch and got the exception message.

Reviewers: jungejason

Reviewed By: jungejason

CC: aran, jungejason

Differential Revision: 839