Move ScrollingMomentumCalculator into the platform directory
Created attachment 438572 [details] Patch
Created attachment 438573 [details] Patch
Created attachment 438575 [details] Patch
Committed r282733 (241870@main): <https://commits.webkit.org/241870@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 438575 [details].
<rdar://problem/83276062>