tools/perf/record_wpr is the script we typically use for recording. Also telemetry/record_wpr.py do rely on webpage_replay_go_server.py. 

What command did you run to reproduce this bug?

Actually I think the higher level question to ask is what is  tools/android/customtabs_benchmark? :-)

Our tech stack around webpage_replay_go_server is not meant to be usable publicly, and it's better if you can work with us to build tools/android/customtabs_benchmark using Telemetry's benchmarking framework.

Yes, exactly. We last used that script with the python wpr server, and now we're starting to look into that again.

This script does benchmarking for CCT features like prefetching, warmup, etc. It does it by launching a native chrome app that only launches a browser via a CCT intent. Hence, it's not clear how to put it into the telemetry framework; I guess the CCT stub app would be a new kind of Browser(), but it's a very limited and special one. The telemetry architecture is a little opaque to outsiders :)

Any suggestions welcome...

Are you aware of Pasko effort to rewrite Telemetry startup benchmark to be more generic & cover cases like CCT? I think this case should also go under that unified clank startup benchmark.

https://docs.google.com/document/d/1sWsM9jt8mrWiN5ngfhVSgfHg2E_Kjls71dhYFI011rg/edit?disco=AAAABakPknk&ts=5a003cb6

Yes, he convinced me to help him with that :)

The easy first step was to get the customtabs benchmark updated from the old WPR server. Given that that now seems not interesting, my previous question holds: there seems to be a need for a new kind of Browser() to handle the CCT launcher app, but we need guidance in how to implement that.

Matt: Juan is already started working on this (tracking bug:  issue 784319 ). The idea is we gonna add an API in telemetry that allows it to extracts all the Chrome browsers on the system instead of create a new kind of Browser(). Code would look s.t like this:

android_platform.LaunchApp('twitter')
android_platform.Tap('id=....')  # -> this triggers CCT
android_platform.WaitFor('id=...')  # Wait for CCT to appear on the screen
alive_browsers = android_platform.GetAllRunningBrowserInstances()
assert len(alive_browsers) == 1
cct_browser = alive_browser[0]
... Do the rest of the user interaction with cct_browser ...

OK, cool. So this is really the same work. Thanks for the clarification.

Marking as dup.