You can inject your css bundle using directly StyleInjector
utility class, instead of the ensureInjected()
method
Then you will have a reference of the injected element which you can remove when you want.
// Equivalent to MyClass.INSTANCE.ensureInjected()
StyleElement e = StyleInjector.injectStylesheet(MyClass.INSTANCE.css().getText());
// Remove the injected css element
e.removeFromParent();