[Impeller] Flutter GPU: Allow specifying uniform and vertex data in a type-safe manner in Dart. #131517
Description
Part of #130921.
The features that we get with C++ code-gen that would be nice to have in Dart would be:
- Type-safe.
- Updates to uniforms and vertex layouts in shaders will cause compiler errors.
- Minimizes copies when possible.
Some of all of these would be nice to have but by no means necessary for an MVP.