AtomicString SrcSchemeToURL(TestURLScheme scheme) {
  switch (scheme) {
    case TestURLScheme::kHttp:
      return "http://example.com/foo.mp4";
    case TestURLScheme::kHttps:
      return "https://example.com/foo.mp4";
    case TestURLScheme::kFtp:
      return "ftp://example.com/foo.mp4";
    case TestURLScheme::kFile:
      return "file:///foo/bar.mp4";
    case TestURLScheme::kData:
      return "data:video/mp4;base64,XXXXXXX";
    case TestURLScheme::kBlob:
      return "blob:http://example.com/00000000-0000-0000-0000-000000000000";
    default:
      NOTREACHED();
  }
  return g_empty_atom;
}

Unknown