Add visualbench option for nvpr stencil samples

tools/VisualBench/VisualBenchmarkStream.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  */
 
 #include <VisualBench/VisualBenchmarkStream.h>
 #include <VisualBench/WrappedBenchmark.h>
@@ skipping 113 matching lines @@
         while ((bench = this->innerNext()) &&
                (SkCommandLineFlags::ShouldSkip(FLAGS_match, bench->getUniqueName()) ||
                 !bench->isSuitableFor(Benchmark::kGPU_Backend))) {
             bench->unref();
         }
     }
 
     // TODO move this all to --config
     if (bench && FLAGS_cpu) {
         bench = new CpuWrappedBenchmark(fSurfaceProps, bench);
-    } else if (bench && FLAGS_nvpr) {
-        bench = new NvprWrappedBenchmark(fSurfaceProps, bench, 4);
+    } else if (bench && 0 != FLAGS_nvpr) {
+        bench = new NvprWrappedBenchmark(fSurfaceProps, bench, FLAGS_nvpr);
     }
 
     fBenchmark.reset(bench);
     return fBenchmark;
 }
 
 Benchmark* VisualBenchmarkStream::innerNext() {
     while (fBenches) {
         Benchmark* bench = fBenches->factory()(nullptr);
         fBenches = fBenches->next();
@@ skipping 24 matching lines @@
         }
 
         SkString name = SkOSPath::Basename(path.c_str());
         fSourceType = "skp";
         fBenchType = "playback";
         return new VisualSKPBench(name.c_str(), pic.get());
     }
 
     return nullptr;
 }