87bd337836
The linker error was due to the same uniform name with different types appearing in different shader stages. I'll add an Impeller validation for this in a subsequent patch so we don't depend on testing in GLES. There was also another issue related to not being able to bind a cube-map type texture. After these fixes, the showcase runs but the one of the textures doesn't seem to be sampled still. But still, the progress is pretty neat. Fixes https://github.com/flutter/flutter/issues/104585.