Remove uses of SkImageDecoder from samplecode

samplecode/DecodeFile.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmap.h"
+#include "SkCodec.h"
+#include "SkData.h"
+
+inline bool decode_file(const char* filename, SkBitmap* bitmap,
+        SkColorType colorType = kN32_SkColorType, bool requireUnpremul = false) {
+    SkASSERT(kIndex_8_SkColorType != colorType);
+    SkAutoTUnref<SkData> data(SkData::NewFromFileName(filename));
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(data));
+    if (!codec) {
+        return false;
+    }
+
+    SkImageInfo info = codec->getInfo().makeColorType(colorType);
+    if (requireUnpremul && kPremul_SkAlphaType == info.alphaType()) {
+        info = info.makeAlphaType(kUnpremul_SkAlphaType);
+    }
+
+    if (!bitmap->tryAllocPixels(info)) {
+        return false;
+    }
+
+    return SkCodec::kSuccess == codec->getPixels(info, bitmap->getPixels(), bitmap->rowBytes());
+}