Remove uses of SkImageDecoder from samplecode

samplecode/SampleUnpremul.cpp

Index: samplecode/SampleUnpremul.cpp
diff --git a/samplecode/SampleUnpremul.cpp b/samplecode/SampleUnpremul.cpp
index 4e3e1fae97b0967d547b81e9decadcb54a9d7dec..fb9735c017cd771a63762725ab299ad91bf21908 100644
--- a/samplecode/SampleUnpremul.cpp
+++ b/samplecode/SampleUnpremul.cpp
@@ -8,14 +8,13 @@
 #include "gm.h"
 
 #include "sk_tool_utils.h"
+#include "DecodeFile.h"
 #include "Resources.h"
 #include "SampleCode.h"
 #include "SkBlurMask.h"
 #include "SkBlurDrawLooper.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
-#include "SkForceLinking.h"
-#include "SkImageDecoder.h"
 #include "SkOSFile.h"
 #include "SkStream.h"
 #include "SkString.h"
@@ -24,8 +23,6 @@
 #include "SkUtils.h"
 #include "SkView.h"
 
-__SK_FORCE_IMAGE_DECODER_LINKING;
-
 /**
  *  Interprets c as an unpremultiplied color, and returns the
  *  premultiplied equivalent.
@@ -167,17 +164,7 @@ private:
             fDecodeSucceeded = false;
             return;
         }
-        SkFILEStream stream(fCurrFile.c_str());
-        SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
-        if (nullptr == decoder.get()) {
-            fDecodeSucceeded = false;
-            return;
-        }
-        if (!fPremul) {
-            decoder->setRequireUnpremultipliedColors(true);
-        }
-        fDecodeSucceeded = decoder->decode(&stream, &fBitmap, kN32_SkColorType,
-                SkImageDecoder::kDecodePixels_Mode) != SkImageDecoder::kFailure;
+        fDecodeSucceeded = decode_file(fCurrFile.c_str(), &fBitmap, kN32_SkColorType, !fPremul);
         this->inval(nullptr);
     }