getID method
Retrieves an identifier for the app instance. The instance ID will be
returned by the callback. The same ID will be returned as long as the
application identity has not been revoked or expired.
returns Function called when the retrieval completes. It should check
runtime.lastError for error when instanceID is empty.
Implementation
Future<String> getID() async {
var $res = await promiseToFuture<String>($js.chrome.instanceId.getID());
return $res;
}