Support Float32 output from SkColorSpaceXform

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 46 matching lines @@
 
     SkSampler* getSampler(bool createIfNecessary) override;
     void applyXformRow(void* dst, const void* src);
 
     voidp png_ptr() { return fPng_ptr; }
     voidp info_ptr() { return fInfo_ptr; }
 
     SkSwizzler* swizzler() { return fSwizzler; }
 
     // Initialize variables used by applyXformRow.
-    void initializeXformAlphaAndWidth();
+    void initializeXformParams();
 
     /**
      *  Pass available input to libpng to process it.
      *
      *  libpng will call any relevant callbacks installed. This will continue decoding
      *  until it reaches the end of the file, or until a callback tells libpng to stop.
      */
     void processData();
 
 #ifdef SK_GOOGLE3_PNG_HACK
@@ skipping 43 matching lines @@
     bool initializeXforms(const SkImageInfo& dstInfo, const Options&, SkPMColor* colorPtr,
                           int* colorCount);
     void initializeSwizzler(const SkImageInfo& dstInfo, const Options&);
     void allocateStorage(const SkImageInfo& dstInfo);
     void destroyReadStruct();
 
     virtual Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) = 0;
     virtual void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) = 0;
     virtual Result decode(int* rowsDecoded) = 0;
 
-    XformMode   fXformMode;
-    SkAlphaType fXformAlphaType;
-    int         fXformWidth;
+    XformMode                      fXformMode;
+    SkColorSpaceXform::ColorFormat fXformColorFormat;
+    SkAlphaType                    fXformAlphaType;
+    int                            fXformWidth;
 
 #ifdef SK_GOOGLE3_PNG_HACK
     bool        fNeedsToRereadHeader;
 #endif
 
     typedef SkCodec INHERITED;
 };