Firefox Profiler has it
. It is Firefox's next-generation performance tool which will replace the current Performance panel.
For early adopters: https://profiler.firefox.com
It has sharing build in. Here is a flame graph for twitter to play with:
https://profiler.firefox.com/public/a158f59206e7d4fc8b88d79587484bb48d453023/flame-graph/?globalTrackOrder=0&hiddenLocalTracksByPid=75790-0-1&implementation=js&localTrackOrderByPid=75790-0-1~&thread=0&v=4 …pic.twitter.com/SfquxuOLPt