08355df4dc
In the OpenGL ES backend, if an Impeller operation happens on a thread with no OpenGL context current, the reactor enqueues it for later execution. This later execution may happen on the main context. To avoid this pessimization, queue the upload to the IO thread (which already has a context) instead. I was hoping that the reactor would manage task pinning as well but that change is more invasive and I wanted to add parity with the Metal backend ASAP. Hence the post-task fix. Fixes https://github.com/flutter/flutter/issues/104756