Chrome storage quota reporting lower than expected

Are you trying to query using chrome and get the entire available disk space? Because I don't believe this is possible using the queryUsageAndQuota() you can only request more or view the current pool size.

Eg mine comes back a little over 1gb when i try

navigator.webkitTemporaryStorage.queryUsageAndQuota ( function(usedBytes, grantedBytes) {      console.log('we are using ', usedBytes, ' of ', grantedBytes, 'bytes');}, function(e) { console.log('Error', e);  });

Here is a good article explaining the pool size, essentially its never going to report more than half of the available disk space and of that any app can only have 20% of that.

If you just have that one 190gb drive you would think you still have around 19gb as the max for the app!

HOWEVER try hitting chrome://quota-internals/ and for me i found the disk space to be 12.59 GB which when i do the calculations again comes in around the 1.5gb mark then minus any installed apps and already used cache space brings it to the quota limit i got earlier. So Perhaps check the profile size directory. You can also see any other entries in the Usage and Quota tab.

You don't need to ask for more temporary storage as the allocation is automatic, and you can't get beyond the maximum limit (as described in the table).

According to Managing HTML5 Offline Storage part of the documentation.