Remove the redundancy in the name and create dedicated source and header files for the DisplayList::Item. Its functions are currently split between DisplayListItems.cpp and DisplayListReplayer.cpp.
<rdar://problem/114391530>
Pull request: https://github.com/WebKit/WebKit/pull/17028
Committed 267431@main (46e9c071bff4): <https://commits.webkit.org/267431@main> Reviewed commits have been landed. Closing PR #17028 and removing active labels.