Skeleton of DM

dm/DMTask.h

+#ifndef DMTask_DEFINED
+#define DMTask_DEFINED
+
+#include "DMReporter.h"
+#include "SkRunnable.h"
+#include "SkThreadPool.h"
+
+// DM will run() these tasks on one of two threadpools, depending on the result
+// of usesGpu().  The subclasses can call fail() to mark this task as failed,
+// or make any number of spawnChild() calls to kick off dependent tasks.
+//
+// Task deletes itself when run.
+
+namespace DM {
+
+class TaskRunner;
+
+class Task : public SkRunnable {
+public:
+    Task(Reporter* reporter, TaskRunner* taskRunner);
+    Task(const Task& that);
+    virtual ~Task();
+
+    void run();
+
+    virtual void draw() = 0;
+    virtual bool usesGpu() const = 0;
+    virtual bool shouldSkip() const = 0;
+    virtual SkString name() const = 0;
+
+protected:
+    void spawnChild(Task* task);
+    void fail();
+
+private:
+    // Both unowned.
+    Reporter* fReporter;
+    TaskRunner* fTaskRunner;
+};
+
+}  // namespace DM
+
+#endif  // DMTask_DEFINED