Perform color correction on png decodes

src/core/SkColorSpaceXform.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.
  */
 
 #ifndef SkColorSpaceXform_DEFINED
 #define SkColorSpaceXform_DEFINED
 
 #include "SkColorSpace.h"
 #include "SkColorSpace_Base.h"
+#include "SkImageInfo.h"
 
 class SkColorSpaceXform : SkNoncopyable {
 public:
 
-    typedef uint32_t RGBA32;
-    typedef uint32_t BGRA32;
-    typedef uint64_t RGBAF16;
-
     /**
      *  Create an object to handle color space conversions.
      *
      *  @param srcSpace The encoded color space.
      *  @param dstSpace The destination color space.
      *
      */
     static std::unique_ptr<SkColorSpaceXform> New(const sk_sp<SkColorSpace>& srcSpace,
                                                   const sk_sp<SkColorSpace>& dstSpace);
 
     /**
      *  Apply the color conversion to a src buffer, storing the output in the dst buffer.
-     *  The src is stored as RGBA (8888) and is treated as opaque.
-     *  TODO (msarett): Support non-opaque srcs.
+     *  The src is stored as RGBA (8888).  The dst is stored in the format indicated by
+     *  |dstColorType| and is premultiplied by alpha if |premul| is set.
      */
-    virtual void applyToRGBA(RGBA32* dst, const RGBA32* src, int len) const = 0;
-    virtual void applyToBGRA(BGRA32* dst, const RGBA32* src, int len) const = 0;
-    virtual void applyToF16(RGBAF16* dst, const RGBA32* src, int len) const = 0;
+    virtual void apply(void* dst, const uint32_t* src, int len, SkColorType dstColorType,
+                       SkAlphaType dstAlphaType) const  = 0;
 
     virtual ~SkColorSpaceXform() {}
 };
 
-template <SkColorSpace::GammaNamed Dst>
+template <SkColorSpace::GammaNamed kDst>
 class SkColorSpaceXform_Base : public SkColorSpaceXform {
 public:
 
-    void applyToRGBA(RGBA32* dst, const RGBA32* src, int len) const override;
-    void applyToBGRA(BGRA32* dst, const RGBA32* src, int len) const override;
-    void applyToF16(RGBAF16* dst, const RGBA32* src, int len) const override;
+    void apply(void* dst, const uint32_t* src, int len, SkColorType dstColorType,
+               SkAlphaType dstAlphaType) const override;
 
     static constexpr int      kDstGammaTableSize = 1024;
 
 private:
     SkColorSpaceXform_Base(const sk_sp<SkColorSpace>& srcSpace, const SkMatrix44& srcToDst,
                            const sk_sp<SkColorSpace>& dstSpace);
 
     sk_sp<SkColorLookUpTable> fColorLUT;
 
     // May contain pointers into storage or pointers into precomputed tables.
     const float*              fSrcGammaTables[3];
     float                     fSrcGammaTableStorage[3 * 256];
 
     float                     fSrcToDst[16];
 
     // May contain pointers into storage or pointers into precomputed tables.
     const uint8_t*            fDstGammaTables[3];
     uint8_t                   fDstGammaTableStorage[3 * kDstGammaTableSize];
 
     friend class SkColorSpaceXform;
 };
 
 #endif