@Override
    public void onPageFinished(WebView view, String url) {
      synchronized (syncObject) {
        pageDoneLoading = true;
        syncObject.notify();
      }
    }
Unconventional way of adding a Javascript interface but the main reason why I took this way
is that it is working stable compared to the webview.addJavascriptInterface way.
selendroid-server/src/main/java/io/selendroid/server/model/SelendroidWebDriver.java