Good question. So, there's this new Web Tracing Framework: http://google.github.io/tracing-framework/ http://google.github.io/tracing-framework/ And Speed Tr

Good question. So, there's this new Web Tracing Framework: http://google.github.io/tracing-framework/ http://google.github.io/tracing-framework/ And Speed Tracer, as you mention: https://developers.google.com/web-toolkit/speedtracer/ https://developers.google.com/web-toolkit/speedtracer/ And also PageSpeed Tools: https://developers.google.com/speed/pagespeed/ https://developers.google.com/speed/pagespeed/ I'm surprised they don't address the distinction, history, or evolution plan anywhere prominently.