SimpleDialog constructor
Creates a simple dialog.
Typically used in conjunction with showDialog.
The titlePadding and contentPadding arguments must not be null.
Implementation
const SimpleDialog({
  Key key,
  this.title,
  this.titlePadding = const EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 0.0),
  this.children,
  this.contentPadding = const EdgeInsets.fromLTRB(0.0, 12.0, 0.0, 16.0),
  this.semanticLabel,
  this.shape,
}) : assert(titlePadding != null),
     assert(contentPadding != null),
     super(key: key);