Support color xforms for kIndex8 pngs

src/codec/SkPngCodec.h

 /*
  * 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 "SkColorSpaceXform.h"
 #include "SkColorTable.h"
@@ skipping 48 matching lines @@
     std::unique_ptr<SkColorSpaceXform> fColorXform;
     SkAutoTMalloc<uint8_t>             fStorage;
     uint8_t*                           fSwizzlerSrcRow;
     uint32_t*                          fColorXformSrcRow;
     size_t                             fSrcRowBytes;
 
     const int                          fNumberPasses;
     int                                fBitDepth;
 
 private:
-    bool createColorTable(SkColorType dstColorType, bool premultiply, int* ctableCount);
+    bool createColorTable(const SkImageInfo& dstInfo, int* ctableCount);
     void destroyReadStruct();
 
     typedef SkCodec INHERITED;
 };