Bug 947487 - Part 1: Convert DOMJSClass::mBase from JSClass to js::Class. (r=bz)
Bug 947487 - Part 2: Generate and use js::Class structs for DOM proxies. (r=bz)
Bug 924720 - Followup: Remove js::IsProxyClass(clasp), and use clasp->isProxy() instead. (r=jwalden)