private Bundle getSmallIconBitmap() {
        int id = getSmallIconId();
        Bundle bundle = new Bundle();
        if (id == NO_ID) {
            return bundle;
        }
        bundle.putParcelable(KEY_SMALL_ICON_BITMAP,
                BitmapFactory.decodeResource(getResources(), id));
        return bundle;
    }
Returns a list of active notifications, essentially calling
NotificationManager#getActiveNotifications. The default implementation does not work on
pre-Android M.
@return An array of StatusBarNotification.
customtabs/src/android/support/customtabs/trusted/TrustedWebActivityService.java