Use Case:

The SearchDelegate's text field only uses Theme's headline6 font, which would look too small or too large if it's used as a font size for search field (As I have set headline6 that way for my app).

Proposal:

One way was to change headline6 globally, which I don't want as I have designed my app that way to use 12 fontSize of headline6.

So the only possible way to change search field text style was to make the field use searchFieldStyle(if provided), else to use the default headline6.

I have reflected my changes in PR #91982