Text Field Boxes

Is there support for Material Design's [Text Field Boxes](https://material.io/guidelines/components/text-fields.html#text-fields-text-field-boxes) currently and/or planned?

Does anyone know of any 3rd-party implementation?

One point made in the MD spec: "Text field boxes make dense layouts easier to read."

I have a dense form which looks much better when text fields are encapsulated in boxes. With some CSS tweaks I'm able to get fields in rounded-corner boxes, but the positioning of the elements inside needs more work to match the MD spec.

No source file, test, or entry point is named. Start by reviewing the existing text-field implementation against the linked Material Design text-field-box specification, then determine the required markup, styling, and element positioning; done should include a confirmed support status and behavior matching the requested boxed fields.

Written by the indexing model from the issue text.