"Requirements for Powerful Features" strawman.

After talking a bit more with Anne and others, I'm coming around to the
opinion that we should break the "powerful features" bit out of MIX. In
particular, the notion that we need to explain what constitutes a "powerful
feature" pushes this right out of MIX in my mind; it was always tangential,
and if we need to define the category (and I agree that we do), then MIX
isn't the right place for it.

I've slapped together a strawman at
https://w3c.github.io/webappsec/specs/powerfulfeatures/ with lots of TODO
text. If folks agree that a separate document is worthwhile, I'll remove
the copy/pasted bits from MIX, clean up the strawman, and issue a CfC to
publish a FPWD.

Thanks!

--
Mike West <mkwst@google.com>
Google+: https://mkw.st/+, Twitter: @mikewest, Cell: +49 162 10 255 91

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