message: Fix the CPU events filtering logic.
diff: @@ -60,11 +60,11 @@ StepEvents ConvertHostThreadsXLineToStepEvents(
  }
  });
  if (group_id < 0) return;
  - // Don't add events when either (1) it excludes device step events or
  - // (2) it has a device and that the group_id (i.e. step number) already
  + // Don't add CPU events when (1) it includes device step events and (2) it
  + // doesn't have a device and that the group_id (i.e. step number) already
  // appears on the device. This will filter out all cpu events that do not
  // correspond to any steps executed on the device.
  - if (!use_device_step_events ||
  + if (use_device_step_events &&
  device_step_events.find(group_id) == device_step_events.end())
  return;
  Timespan timespan = Timespan(event.TimestampPs(), event.DurationPs());
  