DM: also run benches once.

dm/DMTask.h

 #ifndef DMTask_DEFINED
 #define DMTask_DEFINED
 
 #include "DMReporter.h"
+#include "GrContextFactory.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 {
@@ skipping 14 matching lines @@
     virtual SkString name() const = 0;
 
     // Returns the number of parents above this task.
     // Top-level tasks return 0, their children 1, and so on.
     int depth() const { return fDepth; }
 
 protected:
     void spawnChild(Task* task);
     void fail(const char* msg = NULL);
 
+    // This can only be safely called from a GPU task's draw() method.
+    GrContextFactory* getGrContextFactory() const;
+
 private:
     // Both unowned.
     Reporter* fReporter;
     TaskRunner* fTaskRunner;
     int fDepth;
 
     typedef SkRunnable INHERITED;
 };
 
 }  // namespace DM
 
 #endif  // DMTask_DEFINED