`RefProcPhaseTimeTracker` and `RefProcTotalPhaseTimesTracker` are identical. Both are stack-allocated to keep track the elapsed time and are used exclusively inside `ReferenceProcessor::process_discovered_references` with the same args.

The structure is effectively:

```
{
  RefProcTotalPhaseTimesTracker tt(SoftWeakFinalRefsPhase, &phase_times);
  {
    ...
    RefProcPhaseTimeTracker tt(SoftWeakFinalRefsPhase, &phase_times);
    ...
  }
}
```

As shown, the effect of `RefProcPhaseTimeTracker` is shadowed by `RefProcTotalPhaseTimesTracker` in the outer scope. Therefore, `class RefProcPhaseTimeTracker` can be removed with no externally visible effect.