Move threadpool code from include/utils to tools/threadpool.

tests/OnceTest.cpp

Index: tests/OnceTest.cpp
diff --git a/tests/OnceTest.cpp b/tests/OnceTest.cpp
index 389d257b73fdb3a8aa25be023f6f48750cd2bb2f..ec79a2543a11855fbf1d6d2e0ce5f68fb04b78b5 100644
--- a/tests/OnceTest.cpp
+++ b/tests/OnceTest.cpp
@@ -6,7 +6,7 @@
  */
 
 #include "SkOnce.h"
-#include "SkThreadPool.h"
+#include "ThreadPool.h"
 #include "Test.h"
 
 static void add_five(int* x) {
@@ -31,7 +31,7 @@ static void add_six(int* x) {
     *x += 6;
 }
 
-class Racer : public SkRunnable {
+class Racer : public Runnable {
 public:
     SkOnceFlag* once;
     int* ptr;
@@ -54,7 +54,7 @@ DEF_TEST(SkOnce_Multithreaded, r) {
     }
 
     // Let them race.
-    SkThreadPool pool(kThreads);
+    ThreadPool pool(kThreads);
     for (int i = 0; i < kTasks; i++) {
         pool.add(&racers[i]);
     }