Fix compilation of benchHistFactory

The interface to store and retrieve the minimization path was removed.
It was not necessary anymore, because by now all backends that are
benchmarked behave the same and therefore the minimizer follows the same
minimization path.

root/roofit/histfactory/benchHistFactory.cxx

@@ -31,28 +31,10 @@ class TestData {
          constraintParams.add(*mc->GetParametersOfInterest());
       if (mc->GetNuisanceParameters())
          constraintParams.add(*mc->GetNuisanceParameters());
-
-      auto *pdf = ws->pdf("simPdf");
-
-      std::unique_ptr<RooAbsReal> nll{pdf->createNLL(*ws->data("obsData"), Constrain(constraintParams),
-                                                     GlobalObservables(*mc->GetGlobalObservables()), EvalBackend::Legacy())};
-
-      RooMinimizer m(*nll);
-      m.setPrintLevel(-1);
-      m.setStrategy(0);
-      m.setLoggingToDataSet(true);
-
-      m.minimize("Minuit2");
-
-      minimizationPath = std::make_unique<RooDataSet>(*m.getLogDataSet());
    }
 
    std::unique_ptr<RooWorkspace> ws;
 
-   // Dataset with the floating parameters as columns, and each call to getVal
-   // in the minimization path as rows.
-   std::unique_ptr<RooDataSet> minimizationPath;
-
    // The constraint parameters in the model.
    RooArgSet constraintParams;
 };
@@ -77,22 +59,23 @@ static void benchHistFactory001(benchmark::State &state)
                                                   GlobalObservables(*mc->GetGlobalObservables()),
                                                   EvalBackend(evalBackend))};
 
-   auto &minimizationPath = *g_testData.minimizationPath;
-
-   RooArgSet parameters{};
+   RooArgSet parameters;
+   RooArgSet initialParams;
    nll->getParameters(nullptr, parameters);
+   parameters.snapshot(initialParams);
 
    // The minimization path depends on the configuration in unpredictable ways.
    // That's why we don't use the RooMinimizer each time, but only "emulate" a
    // fit by taking a reference minimization path.
 
    for (auto _ : state) {
-      for (auto i = 0; i < minimizationPath.numEntries(); ++i) {
-         state.PauseTiming();
-         parameters.assign(*minimizationPath.get(i));
-         state.ResumeTiming();
-         nll->getVal();
-      }
+      state.PauseTiming();
+      parameters.assign(initialParams);
+      RooMinimizer m(*nll);
+      m.setPrintLevel(-1);
+      m.setStrategy(0);
+      state.ResumeTiming();
+      m.minimize("Minuit2");
    }
 }