Retrieval of the max storage amount is now done via the
maxStorageSamples property indicates the maximum number of date usage chunks stored for each type of connection.
A data usage chunk is a
MozNetworkStatsData object representing the total number of bytes received and sent during a given amount of time (this amount of time is accessible through the
var max = navigator.mozNetworkStats.maxStorageSamples;
Not part of any specification.