Added two methods to Diskprovider:- getFixedDrives, getTotalSize and letting UI decide on how to display space. and changed from vent to listenTo (cherry picked from commit 5aa00cfb6498d4731d5d880c346afe747a61024e)
(cherry picked from commit 91625019378247b1c6ab85afaee23f2855e3298b)