Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Use case

Currently, two classes in the framework use MaterialStateMixin

1. material/chip.dart
2. material/button.dart (to be deprecated widget)

While working on #115827, I noticed this.
Every other class in the framework uses a set of MaterialState, which is updated for different states within the widget.

Proposal

My proposal is, either to make chip.dart consistent with the rest of the framework to maintain material states by removing MaterialStateMixin and using a set of material state
or
continue using MaterialStateMixin and consider why MaterialStateMixin is needed.