Use case

when using showDatePicker we have the option to set locale

showDatePicker(
  locale: Locale('en'),
  ...

But when we have multiple of this widget across our app setting this locale individually is cumbersome and feels against best practices.
We do have a class to set the global theme DatePickerThemeData, but this class does not support locale.

Proposal

Include locale property in DatePickerThemeData so that we may globaly set the locale for showDatePicker.