I haven't seen anything talk to the chromecast with low enough latency to play a game more advanced than solitaire. Hell, netflix has enough trouble for me registering when i press the pause/play button.
Oh... Short of running the emulator on a desktop and using desktop mirroring (which has even more latency), not yet...
And as gianptune said, there's too much latency to use Chromecast like this unless the emulator runs on Chromecast. But then there's no way to provide the input control, so it would still require development on the emulator.
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