DM: also run benches once.

dm/DMGpuTask.h

 #ifndef DMGpuTask_DEFINED
 #define DMGpuTask_DEFINED
 
 #include "DMExpectations.h"
 #include "DMReporter.h"
 #include "DMTask.h"
 #include "DMTaskRunner.h"
 #include "GrContextFactory.h"
 #include "SkBitmap.h"
 #include "SkString.h"
 #include "SkTemplates.h"
 #include "gm.h"
 
 // This is the main entry point for drawing GMs with the GPU.
 
 namespace DM {
 
 class GpuTask : public Task {
 public:
-    GpuTask(const char* name,
+    GpuTask(const char* config,
             Reporter*,
             TaskRunner*,
             const Expectations&,
             skiagm::GMRegistry::Factory,
-            SkColorType,
             GrContextFactory::GLContextType,
             int sampleCount);
 
     virtual void draw() SK_OVERRIDE;
     virtual bool usesGpu() const SK_OVERRIDE { return true; }
     virtual bool shouldSkip() const SK_OVERRIDE;
     virtual SkString name() const SK_OVERRIDE { return fName; }
 
 private:
-    TaskRunner* fTaskRunner;
     SkAutoTDelete<skiagm::GM> fGM;
     const SkString fName;
     const Expectations& fExpectations;
-    const SkColorType fColorType;
     const GrContextFactory::GLContextType fContextType;
     const int fSampleCount;
 };
 
 }  // namespace DM
 
 #endif  // DMGpuTask_DEFINED