Make ScrollAnimation a little more generic
Created attachment 438438 [details] Patch
Created attachment 438442 [details] Patch
Created attachment 438444 [details] Patch
Created attachment 438494 [details] Patch
Committed r282697 (241834@main): <https://commits.webkit.org/241834@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 438494 [details].
<rdar://problem/83256465>