Adding png scanline decoding to kIndex8

src/codec/SkCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkCodec_libbmp.h"
@@ skipping 72 matching lines @@
     // require a rewind.
     const bool needsRewind = fNeedsRewind;
     fNeedsRewind = true;
     if (!needsRewind) {
         return kNoRewindNecessary_RewindState;
     }
     return fStream->rewind() ? kRewound_RewindState
                              : kCouldNotRewind_RewindState;
 }
 
-SkScanlineDecoder* SkCodec::getScanlineDecoder(const SkImageInfo& dstInfo) {
-    fScanlineDecoder.reset(this->onGetScanlineDecoder(dstInfo));
+SkScanlineDecoder* SkCodec::getScanlineDecoder(const SkImageInfo& dstInfo, const Options* options,
+        SkPMColor ctable[], int* ctableCount) {
+
+    // Set options.
+    Options optsStorage;
+    if (NULL == options) {
+        options = &optsStorage;
+    }
+
+    fScanlineDecoder.reset(this->onGetScanlineDecoder(dstInfo, *options, ctable, ctableCount));
     return fScanlineDecoder.get();
 }
+
+SkScanlineDecoder* SkCodec::getScanlineDecoder(const SkImageInfo& dstInfo) {
+    SkASSERT(kIndex_8_SkColorType != dstInfo.colorType());
+    if (kIndex_8_SkColorType == dstInfo.colorType()) {
+        return NULL;
+    }
+    return this->getScanlineDecoder(dstInfo, NULL, NULL, NULL);
+}