Such tool is essential for us to track and improve the Fluter power/energy usage. (Search for "percentage" on https://flutter-dashboard.appspot.com/benchmarks.html.) For example, it provides us clear metrics on how to solve the following issue that's blocking one of our very important customers: #31865.

Unfortunately, that tool currently relies on TraceUtility which doesn't work properly on Xcode 11. Moreover, we've seen some flakiness: #45194

It would be nice if we can either improve TraceUtility, or create our own version of that tool, to parse Instrument trace documents reliably with Xcode 11. That way, we'll

1. unblock the infra team to upgrade all our Macs to Xcode 11, and reduce the maintenance cost
2. reduce test flakiness and make the whole team happier
3. enlighten our customers by providing better and more reliable power usage metrics for improvements.

EDIT: we recently also found that TraceUtility doesn't work well with iOS 12.4 even if Xcode is still in 10.3. As a workaround, we've switched the iOS version to 12.3 to keep the test working.