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

dm/DM.cpp

Index: dm/DM.cpp
diff --git a/dm/DM.cpp b/dm/DM.cpp
index 12ce23c6a1ef67864fa4304a93943939fa651285..06a8fbff6cc49313a3eedc343fe2585a0f3b357e 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -64,7 +64,6 @@ DEFINE_string(uninterestingHashesFile, "",
 
 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;
@@ -847,7 +846,10 @@ struct Task {
             SkBitmap bitmap;
             SkDynamicMemoryWStream stream;
             if (FLAGS_pre_log) {
-                SkDebugf("\nRunning %s->%s", name.c_str(), task->sink.tag.c_str());
+                SkDebugf("%sRunning %s->%s",
+                         FLAGS_verbose ? "\n" : "\t",
+                         name.c_str(),
+                         task->sink.tag.c_str());
             }
             start(task->sink.tag.c_str(), task->src.tag, task->src.options, name.c_str());
             Error err = task->sink->draw(*task->src, &bitmap, &stream, &log);
@@ -1056,7 +1058,9 @@ static void run_test(skiatest::Test* test) {
         start("unit", "test", "", test->name);
         GrContextFactory factory;
         if (FLAGS_pre_log) {
-            SkDebugf("\nRunning test %s", test->name);
+            SkDebugf("%sRunning test %s",
+                     FLAGS_verbose ? "\n" : "\t",
+                     test->name);
         }
         test->proc(&reporter, &factory);
     }
@@ -1122,6 +1126,10 @@ int dm_main() {
     SkTaskGroup::Enabler enabled(FLAGS_threads);
     gCreateTypefaceDelegate = &create_from_name;
 
+    if (FLAGS_verbose) {
+        FLAGS_pre_log = true;

[mtklein, 2016/01/25 19:44:35]

?  Let's let people set independent things independently.

[dogben, 2016/01/25 20:18:00]

Done.

+    }
+
     start_keepalive();
 
     gather_gold();