Currently lookup of Object and Instancer attributes is completely duplicated between Cycles, Eevee and Eevee Next. This is bad design, so this patch aims to deduplicate it by introducing a common API in blenkernel. In case of Cycles this requires certain hacks, but according to Brecht it is planned to be rewritten later for more direct access to internal Blender data anyway. Differential Revision: https://developer.blender.org/D16117