[1.7] Allow Review UIs to decide whether they're usable on a case-by-case basis.

Review Request #6007 — Created June 17, 2014 and submitted — Latest diff uploaded


Review Board


ReviewUI subclaseses can now define a is_enabled_for() function, which
returns whether it can be enabled for the given user, review request,
and/or file attachment. This allows, for instance, limiting a review UI
based on extra_data on an object, or based on the given user or
Local Site, or anything else.

Tested this with a file attachment returning True, and then returning False.

Implemented a custom version and tested by file attachment name.