hideSplashDom function
void
hideSplashDom()
Fades the splash out and removes it from the page.
Implementation
void hideSplashDom() {
final splash = _document.getElementById(_splashId);
if (splash == null) return;
splash.classList.add(_hiddenClass);
// Interop members can not be torn off.
// ignore: unnecessary_lambdas
Timer(_removeDelay, () => splash.remove());
}