[1] Remove CanvasProxy along with related concepts and complexities · whatwg/html@740634d (2016-03-08 18:40:51 +09:00 版) <https://github.com/whatwg/html/commit/740634d0f30a3b76e9da166ac2fa8835fcc073ab>

[2] Mention origin-clean in OffscreenRenderingContext2D's commit() steps (junov著, 2016-12-13 05:22:15 +09:00) <https://github.com/whatwg/html/commit/23c423a0cfb5ade4e91f54d9c4af93460dba3ed6>