Faster, thread-safe implementation

Bug: skia:
Change-Id: I401c5a9885c348aa424ab07b094acecddb209490
Reviewed-on: https://skia-review.googlesource.com/25860
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index 05c475a..95e1211 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -1106,7 +1106,7 @@
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
 
-    initializeEventTracingForTools(&FLAGS_threads);
+    initializeEventTracingForTools();
 
 #if defined(SK_BUILD_FOR_IOS)
     cd_Documents();