Add a DownloadsProxyMap class in preparation for moving the downloads map away from WebContext
Created attachment 179386 [details] Patch
Comment on attachment 179386 [details] Patch r=me but please wait for EWS before landing.
Comment on attachment 179386 [details] Patch Clearing flags on attachment: 179386 Committed r137756: <http://trac.webkit.org/changeset/137756>
All reviewed patches have been landed. Closing bug.