add browser tab performance stat info to plot overlay?

[vkottler]

find somewhere to show this info (if it can be queried)

[vkottler]

https://developer.mozilla.org/en-US/docs/Web/API/Performance

[vkottler]

could put in leftmost button tab

[vkottler]

don't see any info exposed by browser interfaces, could do a basic frames-per-second counter