@Override
        public Bundle notifyNotificationWithChannel(Bundle bundle) {
            checkCaller();

            NotifyNotificationArgs args = NotifyNotificationArgs.fromBundle(bundle);

            boolean success = TrustedWebActivityService.this.notifyNotificationWithChannel(
                    args.platformTag, args.platformId, args.notification, args.channelName);

            return new ResultArgs(success).toBundle();
        }
Used as a return value of {@link #getSmallIconId} when the icon is not provided.
customtabs/src/android/support/customtabs/trusted/TrustedWebActivityService.java