1. @DomName('Navigator.registerProtocolHandler')
  2. @DocsEditable()
  3. @Unstable()
void registerProtocolHandler(String scheme, String url, String title)

Source 

@DomName('Navigator.registerProtocolHandler')
@DocsEditable()
@Unstable()
void registerProtocolHandler(String scheme, String url, String title) =>
    _blink.BlinkNavigator.instance
        .registerProtocolHandler_Callback_3_(this, scheme, url, title);