tonihei adc23e8e8b Add icon constants to CommandButton
These allow to set the icon in a standardized way without needing
custom bitmaps or resources. For now, this is just additional
information without backwards-compatible icons or implications.

The same value gets written to the platform session via a new
extras key that can be read and set from sessions not using Media3
yet.

PiperOrigin-RevId: 605670988
2024-02-09 10:37:12 -08:00
..
2021-10-27 09:12:46 +01:00