hide Config in SkImageDecoder -- use SkColorType instead

samplecode/SampleUnpremul.cpp

Index: samplecode/SampleUnpremul.cpp
diff --git a/samplecode/SampleUnpremul.cpp b/samplecode/SampleUnpremul.cpp
index 0b1848df95d4e1606a14ada1aa988795e9bae30f..c84e1d44e8b9fff1a15c131bae18e5e9ecc8317e 100644
--- a/samplecode/SampleUnpremul.cpp
+++ b/samplecode/SampleUnpremul.cpp
@@ -4,6 +4,7 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+
 #include "gm.h"
 #include "SampleCode.h"
 #include "SkBlurMask.h"
@@ -182,8 +183,7 @@ private:
         if (!fPremul) {
             decoder->setRequireUnpremultipliedColors(true);
         }
-        fDecodeSucceeded = decoder->decode(&stream, &fBitmap,
-                                           SkBitmap::kARGB_8888_Config,
+        fDecodeSucceeded = decoder->decode(&stream, &fBitmap, kN32_SkColorType,
                                            SkImageDecoder::kDecodePixels_Mode);
         this->inval(NULL);
     }