Revert of SkThreadPool ~~> SkTaskGroup

dm/DMQuiltTask.cpp

 #include "DMQuiltTask.h"
 #include "DMUtil.h"
 #include "DMWriteTask.h"
 
 #include "SkBBHFactory.h"
 #include "SkCommandLineFlags.h"
 #include "SkPicture.h"
-#include "SkTaskGroup.h"
+#include "SkThreadPool.h"
 
 DEFINE_bool(quilt, true, "If true, draw GM via a picture into a quilt of small tiles and compare.");
 DEFINE_int32(quiltTile, 256, "Dimension of (square) quilt tile.");
 
 namespace DM {
 
 static SkString suffix(QuiltTask::Backend backend, QuiltTask::BBH bbh) {
     static const char* kBackends[] = { "default", "skrecord" };
     static const char* kBBHs[]     = { "nobbh", "rtree", "tilegrid" };
     return SkStringPrintf("%s-%s", kBackends[backend], kBBHs[bbh]);
@@ skipping 70 matching lines @@
     SkBitmap full;
     AllocatePixels(fReference, &full);
 
     if (fGM->getFlags() & skiagm::GM::kSkipTiled_Flag) {
         // Some GMs don't draw exactly the same when tiled.  Draw them in one go.
         SkCanvas canvas(full);
         recorded->draw(&canvas);
         canvas.flush();
     } else {
         // Draw tiles in parallel into the same bitmap, simulating aggressive impl-side painting.
-        SkTaskGroup tg;
+        SkThreadPool pool(SkThreadPool::kThreadPerCore);
         for (int y = 0; y < tiles_needed(full.height(), FLAGS_quiltTile); y++) {
             for (int x = 0; x < tiles_needed(full.width(), FLAGS_quiltTile); x++) {
                 // Deletes itself when done.
-                tg.add(new Tile(x, y, *recorded, &full));
+                pool.add(new Tile(x, y, *recorded, &full));
             }
         }
     }
 
     if (!BitmapsEqual(full, fReference)) {
         this->fail();
         this->spawnChild(SkNEW_ARGS(WriteTask, (*this, full)));
     }
 }
 
 bool QuiltTask::shouldSkip() const {
     if (fGM->getFlags() & skiagm::GM::kSkipPicture_Flag) {
         return true;
     }
     return !FLAGS_quilt;
 }
 
 }  // namespace DM