BUG #14275. Expose hidden representations property.

Exposing hidden representations property from comparative render view so that 3D
widget are rendering correctly in comparative view. This addresses the warning
messages reported by the bug report #14275.

Change-Id: I904251bb89ae0549a5d060b02bad081d73ac3a69
Merge topic '14275_fix_comparative_view' into next

ebf0ea6 BUG #14275. Expose hidden representations property.