DM: also run benches once.

dm/DMUtil.h

Index: dm/DMUtil.h
diff --git a/dm/DMUtil.h b/dm/DMUtil.h
index a79164946ea56068f793e6ac4466ebbfdb342175..faa4e39737fe8af007e28da726a519577ac52247 100644
--- a/dm/DMUtil.h
+++ b/dm/DMUtil.h
@@ -1,6 +1,7 @@
 #ifndef DMUtil_DEFINED
 #define DMUtil_DEFINED
 
+#include "SkBenchmark.h"
 #include "SkBitmap.h"
 #include "SkString.h"
 #include "gm_expectations.h"
@@ -15,8 +16,10 @@ SkString UnderJoin(const char* a, const char* b);
 // Draw gm to picture.  Passes recordFlags to SkPicture::beginRecording().
 void RecordPicture(skiagm::GM* gm, SkPicture* picture, uint32_t recordFlags = 0);
 
-// Prepare bitmap to have gm draw into it with this config.
+// Prepare bitmap to have gm or bench draw into it with this config.
+// TODO(mtklein): make SkBenchmark::getSize()/GM::getISize() const.
 void SetupBitmap(const SkColorType, skiagm::GM* gm, SkBitmap* bitmap);
+void SetupBitmap(const SkColorType, SkBenchmark* bench, SkBitmap* bitmap);
 
 // Draw picture to bitmap.
 void DrawPicture(SkPicture* picture, SkBitmap* bitmap);