Move KeyboardScroll into platform code
Created attachment 441162 [details] Patch
Created attachment 441177 [details] Patch
Created attachment 441178 [details] Patch
Committed r284166 (242986@main): <https://commits.webkit.org/242986@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 441178 [details].
<rdar://problem/84259510>