Convert Configurable.AddPostProcessor to take an interface Configurable.AddPostProcessor takes a function pointer and stores it in the Configurable. This makes any property struct with a Configurable that has AddPostProcessor on it not cacheable. Take an interface instead so that the type that implements the interface can be hashed. Test: TestPostProcessor Change-Id: I89065787ebd8658e5f4c71ef5ac49301a4760cd0