Move code that can be shared to the base classes, clean up existing code.
Created attachment 345574 [details] Patch
<rdar://problem/42500215>
Created attachment 345666 [details] Patch for landing
Created attachment 345671 [details] Patch for landing
Comment on attachment 345671 [details] Patch for landing Clearing flags on attachment: 345671 Committed r234146: <https://trac.webkit.org/changeset/234146>
Created attachment 345696 [details] Build fix
Comment on attachment 345696 [details] Build fix Clearing flags on attachment: 345696 Committed r234164: <https://trac.webkit.org/changeset/234164>
All reviewed patches have been landed. Closing bug.