Add subclassing support to Promise::Race. r=baku,efaust (#2402)

Note that the web platform tests don't actually have quite the behavior they're
expected to per the spec yet.  They will get adjusted later on as we add
subclassing support to Promise.resolve and Promise.prototype.then.

Upstreamed from https://bugzilla.mozilla.org/show_bug.cgi?id=1170760

View on GitHub: https://github.com/w3c/web-platform-tests/pull/2402

Received on Wednesday, 2 December 2015 15:09:02 UTC