add autotuning to visualbench

tools/VisualBench.h

Index: tools/VisualBench.h
diff --git a/tools/VisualBench.h b/tools/VisualBench.h
index 9d7b946afec9598b6e0b82850c494f219ef9d39a..332fe82eb438a12123f27271bea3eee32c5e33cc 100644
--- a/tools/VisualBench.h
+++ b/tools/VisualBench.h
@@ -54,14 +54,19 @@ private:
     };
 
     enum State {
-        kPreWarm_State,
+        kPreWarmLoops_State,
+        kTuneLoops_State,
+        kPreWarmTiming_State,
         kTiming_State,
     };
+    void preWarm(State nextState);
 
-    int fLoop;
     int fCurrentPictureIdx;
     SkAutoTUnref<SkPicture> fPicture;
     int fCurrentSample;
+    int fCurrentFrame;
+    int fFlushes;
+    int fLoops;
     SkTArray<Record> fRecords;
     WallTimer fTimer;
     State fState;