5 years ago (18b693bdbd) part of cache rendering was converted to not
draw one quad at a time. However the other part (drawing strip
backgrounds when cache visualization is on) was left still drawing one
quad at a time.
Now that sequencer timeline drawing code has SeqQuadsBatch that batches
arbitrary number of things for drawing fairly easily, the existing
cache drawing batching code can be simplified to just use that, and
the background code changed from immediate quad drawing to use the
batcher.
Sprite Fright edit, whole timeline visible, all caches visualized and
full: `draw_cache_view` on Windows/Ryzen5950X goes 2.40ms -> 0.16ms.
And there's less code.
Pull Request: https://projects.blender.org/blender/blender/pulls/118027
6f7ac2be53