third_party/web_platform_tests/WebIDL/valid/idl/overridebuiltins.widl

// Extracted from http://dev.w3.org/2006/webapi/WebIDL/ on 2011-05-06
[OverrideBuiltins]
interface StringMap2 {
  readonly attribute unsigned long length;
  getter DOMString lookup(DOMString key);
};