There should be no user visible change from this, except that tile size now affects performance. The goal here is to simplify bake denoising in D3099, letting it reuse more denoising tiles and pass code. A lot of code is now shared with regular rendering, with the two main differences being that we read some render result passes from the bake API when starting to render a tile, and call the bake kernel instead of the path trace kernel. With this kind of design where Cycles asks for tiles from the bake API, it should eventually be easier to reduce memory usage, show tiles as they are baked, or bake multiple passes at once, though there's still quite some work needed for that. Reviewers: #cycles Subscribers: monio, wmatyjewicz, lukasstockner97, michaelknubben Differential Revision: https://developer.blender.org/D3108