hide SkBitmap::setConfig

patch from issue 325733002

TBR=scroggo

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/322963002
diff --git a/bench/BitmapRectBench.cpp b/bench/BitmapRectBench.cpp
index affed72..32589fc 100644
--- a/bench/BitmapRectBench.cpp
+++ b/bench/BitmapRectBench.cpp
@@ -55,7 +55,7 @@
         fFilterLevel = filterLevel;
         fSlightMatrix = slightMatrix;
 
-        fBitmap.setConfig(SkBitmap::kARGB_8888_Config, kWidth, kHeight);
+        fBitmap.setInfo(SkImageInfo::MakeN32Premul(kWidth, kHeight));
     }
 
 protected: