anchor.diff:        // Build the trace events.
         for (final sample in cpuSamples.samples) {
           final tree = _CpuProfileTimelineTree.getTreeFromSample(sample);
  +        // Skip the root.
  +        if (tree.frameId == kRootId) {
  +          continue;
  +        }
           traceObject[CpuProfileData.traceEventsKey].add({
             'ph': 'P', // kind = sample event
             'name': '', // Blank to keep about:tracing happy
  
positive.code:       // and has been replaced by getCpuSamples. We need to do some processing to
        // get back to the format we expect.
        final cpuSamples = await getCpuSamples(isolateId, origin, extent);
        const int kRootId = 0;
        int nextId = kRootId;
        final traceObject = <String, dynamic>{
  
negative.code:         final id = nextId++;
          current.frameId = id;
  
          // Skip the root.
          if (id != kRootId) {
            final key = '$isolateId-$id';
            traceObject[CpuProfileData.stackFramesKey][key] = {
  