This uses floating-point (Layout) coordinates in where possible.
Replace NormalBorder struct with WebRender equivalent.
Remove ToPointF and ToRectF traits.
Convert border RepeatKeyword with ToLayout.
Add some definitions to malloc_size_of for WebRender types.
Move display_list_builder.rs and webrender_helpers.rs
along with the new file to components/layout/display_list/
Remove apparently unused IdType enum.
Only variant used was OverflowClip.
See #19676