First triangle, in the framework! 🎉
Adds shader libraries, pipelines, command buffers, render passes, etc.
* Light pipelines/shader objects. No optimization yet, pipeline warming
to come.
* "Dynamic" command style. Don't re-send bindings if you don't need to.
Essentially: https://github.com/flutter/flutter/issues/133179
* No need to explicitly encode passes.
* Minimal descriptor usage.
* Nothing is async, except for the optional command buffer completion
callback.
It took a bunch of experimenting to get here, but I think things are
starting to look pretty neat. :)
Todo:
* Land the shader bundle format/remove the testing hacks & fixtures that
piggyback off of the runtime effect system.
* Add remaining calls for blend config, clearing bindings, etc.
* Inconsistent error handling patterns that need cleanup.
* Maybe: Surface exceptions for validation errors.
* Handle the texture usage bitmask more elegantly.
