WebFramePolicyListener should keep its Frame in a RefPtr
https://bugs.webkit.org/show_bug.cgi?id=116322

Reviewed by Darin Adler.

* WebCoreSupport/WebFrameLoaderClient.mm:
(-[WebFramePolicyListener initWithWebCoreFrame:]):
No need to ref the frame, the RefPtr does that for us.

(-[WebFramePolicyListener invalidate]):
Just set the frame to null.

(-[WebFramePolicyListener dealloc]):
Remove call to deref, that's done automatically now.

(-[WebFramePolicyListener finalize]):
Remove this method. (We could have kept it just for the assertion but I didn't think that was necessary).

(-[WebFramePolicyListener receivedPolicyDecision:):
Use release() to transfer ownership.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150265 268f45cc-cd09-0410-ab3c-d52691b4dbfc