Skeleton of DM

dm/DMTaskRunner.h

Index: dm/DMTaskRunner.h
diff --git a/dm/DMTaskRunner.h b/dm/DMTaskRunner.h
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+#ifndef DMTaskRunner_DEFINED
+#define DMTaskRunner_DEFINED
+
+#include "SkThreadPool.h"
+#include "SkTypes.h"
+
+// TaskRunner runs Tasks on one of two threadpools depending on the Task's usesGpu() method.
+// This lets us drive the GPU with a small number of threads (e.g. 2 or 4 can be faster than 1)
+// while not swamping it with requests from the full fleet of threads that CPU-bound tasks run on.
+
+namespace DM {
+
+class Task;
+
+class TaskRunner : SkNoncopyable {
+public:
+    TaskRunner(int cputhreads, int gpuThreads);
+
+    void add(Task* task);
+    void wait();
+
+private:
+    SkThreadPool fMain, fGpu;
+};
+
+}  // namespace DM
+
+#endif  // DMTaskRunner_DEFINED