Avoid unnecessary measurements (#409)
Avoid unnecessary measurements (#409)

If "Trace React Updates" is disabled, don't spend time measuring nodes.
This gives significant perf improvements in DEV on pages with many nodes.
aarondancer/react-devtools,jhen0409/react-devtools,aarondancer/react-devtools,jhen0409/react-devtools,aarondancer/react-devtools,jhen0409/react-devtools