Add sk_parallel_for()

tests/PathOpsSkpClipTest.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 "OverwriteLine.h"
 #include "Resources.h"
@@ skipping 285 matching lines @@
     }
 };
 
 TestRunner::~TestRunner() {
     for (int index = 0; index < fRunnables.count(); index++) {
         SkDELETE(fRunnables[index]);
     }
 }
 
 void TestRunner::render() {
-    SkTaskGroup tg;
-    for (int index = 0; index < fRunnables.count(); ++ index) {
-        tg.add(fRunnables[index]);
-    }
+    // TODO: this doesn't really need to use SkRunnables any more.
+    // We can just write the code to run in the for-loop directly.
+    sk_parallel_for(fRunnables.count(), [&](int i) {
+        fRunnables[i]->run();
+    });
 }
 
 ////////////////////////////////////////////////
 
 
 static int similarBits(const SkBitmap& gr, const SkBitmap& sk) {
     const int kRowCount = 3;
     const int kThreshold = 3;
     int width = SkTMin(gr.width(), sk.width());
     if (width < kRowCount) {
@@ skipping 784 matching lines @@
     }
     SkGraphics::Term();
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif