Variablize lowMemoryThreshold to keep tabs open
Created by: UniversalSuperBox
I've noticed that in morph-browser, the out-of-memory tab loader was a
bit excessive. For some reason, it would unload tabs even when the
system had lots of memory available -- 1GB or more!
Turns out, the freeMemRatio < 0.2
test always returned true, no
matter what. I'm not sure why this happens, probably a QML+JS quirk.
By moving the low memory threshold into a new variable, the test
returns correctly based on the amount of available memory in the system.
No more unloading of every tab!
Fixes ubports/morph-browser#99