Enable Objective-C weak references in the WebKit project as a baby step towards enabling ARC.
This will let the WebKit project use the 'weak' attribute with Objective-C properties prior to enabling ARC.
(Where ARC is already enabled in a couple of test projects, we don't explicitly re-enable weak references as ARC already provides them.)
Created attachment 338348 [details]
Note that there are important steps to take when updating ANGLE. See http://trac.webkit.org/wiki/UpdatingANGLE
Committed r230824: <https://trac.webkit.org/changeset/230824>