New Canvas Stuff - HTTP 203

Jake and Surma talk about new things involving the Canvas API. Including, but not limited to:

OffscreenCanvas: https://developers.google.com/web/updates/2018/08/offscreen-canvas
Low-latency mode: https://docs.google.com/document/d/1-Z_dj9AQ4SjgDLAEY3ELR0YrlHR3JZyJPhaHAstS5WU/edit