Cookies: local and server clock out-of-sync

[annevk]

https://bugzilla.mozilla.org/show_bug.cgi?id=1909980#c5

Chrome computes the expiration time by adding the delta between the local and server times. If your computer is 10 hours in the future, the cookie expiration time will be increased by 10 hours. As far as I know, this is not part of the cookie spec (rfc6265bis), but we should implement the same logic.

Now that Firefox has copied this logic, we should probably add it to the specification. Especially given that websites might break in clients that don't do this.

cc @guoye-zhang