pub trait CacheStorageMethods<D: DomTypes> {
// Required methods
fn Has(&self, cx: &mut JSContext, cacheName: DOMString) -> Rc<D::Promise>;
fn Open(&self, cx: &mut JSContext, cacheName: DOMString) -> Rc<D::Promise>;
fn Delete(&self, cx: &mut JSContext, cacheName: DOMString) -> Rc<D::Promise>;
}