Migrate FSlateRenderBatch index poputation to a simple static array return in boxes, borders, and aliased lines.
#rb Patrick.Boutot, Yohann.Dossantos
#jira UE-173455
#preflight 63b745c1d862fdd347cc2d35
[CL 23602247 by daren cheng in ue5-main branch]
#rnx
#rb none
#ROBOMERGE-SOURCE: CL 10869240 via CL 10869516 via CL 10869902
#ROBOMERGE-BOT: (v613-10869866)
[CL 10870584 by ryan durand in Main branch]
This change makes it possible to remove the layout and painting overhead that Slate performs every frame. The system is off by default as we continue to iterate on it.
However, this includes massive changes to batching, rendering, hit testing, and invalidation panels which are permanent changes and cannot be disabled.
#rb chris.gagnon, nick.darnell
[CODEREVIEW] nick.darnell
#ROBOMERGE-OWNER: matt.kuhlenschmidt
#ROBOMERGE-AUTHOR: matt.kuhlenschmidt
#ROBOMERGE-SOURCE: CL 7232617 via CL 7235502
#ROBOMERGE-BOT: (v367-6836689)
[CL 7235503 by matt kuhlenschmidt in Main branch]