[Preferences] Add infrastructure for generating preferences for WWindows WebKitLegacy
Created attachment 411669 [details] Patch
Created attachment 411670 [details] Patch
Committed r268647: <https://trac.webkit.org/changeset/268647> All reviewed patches have been landed. Closing bug and clearing flags on attachment 411670 [details].
<rdar://problem/70409446>