ApiExtractor: Gather .prototype's prototypes' properties
ApiExtractor: Gather .prototype's prototypes' properties

In the edge case of non-Function "libraries" that have a property named
"prototype", gather properties from "prototype"'s prototype chain, as long as
those properties don't appear to belong to some other interface.

GoogleChromeLabs/confluence,GoogleChromeLabs/confluence,GoogleChromeLabs/confluence