Trace Report UI

This webui implements chrome://traces-internals which shows trace reports collected by background tracing. To test, simply navigating to the URL might be sufficient if traces are present. If no traces, chrome can be started with a trace config to force trace collection:

1. Create a new config.pbtxt file anywhere on your desktop. Copy the config below and save the file.

scenarios: {
  scenario_name: "Test"
  trace_config: {
    data_sources: {
      config: {
        name: "org.chromium.trace_event"
        track_event_config: {
          disabled_categories: ["*"],
          enabled_categories: ["toplevel", "__metadata"]
        },
      }
    }
    data_sources: { config: { name: "org.chromium.trace_metadata" } }
  }
  start_rules: {
    name: "Timer Start"
    delay_ms: 0
  }
  upload_rules: {
    name: "Timer End"
    delay_ms: 5000
  }
}

2. Then compile the proto with:

<outdir>/protoc --encode=perfetto.protos.ChromeFieldTracingConfig \
--proto_path=third_party/perfetto third_party/perfetto/protos/perfetto/config/\
chrome/scenario_config.proto < config.pbtxt > config.pb

config.pbtxt is the absolute path where your file is on your desktop. Keep the < > around config.pbtxt from the command above.

3. And run chrome with command line:

--enable-background-tracing=config.pb

You should be able to now collect trace reports on your computer and preview them on chrome://traces-internals.