web_generator/test/integration/idl/mixin_interfaces_input.idl

interface mixin EventTargetMixin {
  void addEventListener(DOMString type, EventListener callback, optional boolean capture = false);
  void removeEventListener(DOMString type, EventListener callback, optional boolean capture = false);
  boolean dispatchEvent(Event event);
};

interface mixin PositionMixin {
  attribute double x;
  attribute double y;
  void moveTo(double newX, double newY);
};

interface Position {};

Position includes PositionMixin;

interface mixin MyMixin {
  void somethingMixedIn();
};

partial interface mixin Position {
  void somethingMixedIn();
};