mac: Remove OwnershipPolicy parameter to scoped_nsobject.

mac: Remove OwnershipPolicy parameter to scoped_nsobject.

The client code gets shorter, the implementation gets shorter, and there are
fewer concepts to remember.

BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=177200

[Mark Mentovai, 2013-01-15 21:32:18]

We can’t get rid of this. The iPhoneys use it. We added it to support their
needs.

[Nico, 2013-01-15 21:33:17]

On 2013/01/15 21:32:18, Mark Mentovai wrote:
> We can’t get rid of this. The iPhoneys use it. We added it to support their
> needs.

What do they use it for? Why can't they just [foo retain] at the calling site?

[Mark Mentovai, 2013-01-15 21:35:28]

The checkin comment has all of the context that I remember:

https://codereview.chromium.org/9349016

If qsr says that they no longer need this API feature then I’ll approve this
change.

[Nico, 2013-01-15 21:39:41]

qsr: Mark says you added this (in https://codereview.chromium.org/9349016). Do
you really need this? What for?

[qsr, 2013-01-16 09:02:12]

Nothing.

 Mark: You asked me to add this when I spoke about changing scoped_nsobject to
be copyable. We do not use this, I prefer to do the retain myself. I'm all for
removing that.

[Mark Mentovai, 2013-01-16 13:19:27]

LGTM then.