Add pre_log option to nanobench; make this option default true in nanobench and dm.

dm/DM.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
@@ skipping 46 matching lines @@
         "'--blacklist gpu skp _ _ 8888 gm _ aarects' will also blacklist the aarects GM on 8888.");
 
 DEFINE_string2(readPath, r, "", "If set check for equality with golden results in this directory.");
 
 DEFINE_string(uninterestingHashesFile, "",
         "File containing a list of uninteresting hashes. If a result hashes to something in "
         "this list, no image is written for that result.");
 
 DEFINE_int32(shards, 1, "We're splitting source data into this many shards.");
 DEFINE_int32(shard,  0, "Which shard do I run?");
-DEFINE_bool2(pre_log, p, false, "Log before running each test. May be incomprehensible when threading");
 
 __SK_FORCE_IMAGE_DECODER_LINKING;
 using namespace DM;
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 static double now_ms() { return SkTime::GetNSecs() * 1e-6; }
 
 SK_DECLARE_STATIC_MUTEX(gFailuresMutex);
 static SkTArray<SkString> gFailures;
@@ skipping 1204 matching lines @@
                                                            Reporter* reporter,
                                                            GrContextFactory* factory);
 } // namespace skiatest
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif