Have nanobench pay attention to --threads.

bench/nanobench.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <ctype.h>
 
 #include "nanobench.h"
@@ skipping 917 matching lines @@
     int fCurrentColorType;
     int fCurrentSubsetType;
     int fUseCodec;
     int fCurrentAnimSKP;
 };
 
 int nanobench_main();
 int nanobench_main() {
     SetupCrashHandler();
     SkAutoGraphics ag;
-    SkTaskGroup::Enabler enabled;
+    SkTaskGroup::Enabler enabled(FLAGS_threads);
 
 #if SK_SUPPORT_GPU
     GrContextOptions grContextOpts;
     grContextOpts.fDrawPathToCompressedTexture = FLAGS_gpuCompressAlphaMasks;
     gGrFactory.reset(SkNEW_ARGS(GrContextFactory, (grContextOpts)));
 #endif
 
     if (FLAGS_veryVerbose) {
         FLAGS_verbose = true;
     }
@@ skipping 205 matching lines @@
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif