Delete reallyHasAlpha() from SkCodec

src/codec/SkCodec_libpng.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 "SkColorTable.h"
 #include "SkPngChunkReader.h"
@@ skipping 14 matching lines @@
     static SkCodec* NewFromStream(SkStream*, SkPngChunkReader* = NULL);
 
     virtual ~SkPngCodec();
 
 protected:
     Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*, int*)
             override;
     SkEncodedFormat onGetEncodedFormat() const override { return kPNG_SkEncodedFormat; }
     bool onRewind() override;
     uint32_t onGetFillValue(SkColorType colorType, SkAlphaType alphaType) const override;
-    bool onReallyHasAlpha() const final;
 
     // Helper to set up swizzler and color table. Also calls png_read_update_info.
     Result initializeSwizzler(const SkImageInfo& requestedInfo, const Options&,
                               SkPMColor*, int* ctableCount);
     SkSampler* getSampler(bool createIfNecessary) override {
         SkASSERT(fSwizzler);
         return fSwizzler;
     }
 
     SkPngCodec(const SkImageInfo&, SkStream*, SkPngChunkReader*, png_structp, png_infop, int, int);
 
     png_structp png_ptr() { return fPng_ptr; }
     SkSwizzler* swizzler() { return fSwizzler; }
     SkSwizzler::SrcConfig srcConfig() const { return fSrcConfig; }
     int numberPasses() const { return fNumberPasses; }
 
-    enum AlphaState {
-        // This class has done no decoding, or threw away its knowledge (in
-        // scanline decodes).
-        kUnknown_AlphaState,
-        // This class found the image (possibly partial, in the case of a
-        // scanline decode) to be opaque.
-        kOpaque_AlphaState,
-        // Ths class found the image to have alpha.
-        kHasAlpha_AlphaState,
-    };
-
-    virtual AlphaState alphaInScanlineDecode() const = 0;
-
 private:
     SkAutoTUnref<SkPngChunkReader>  fPngChunkReader;
     png_structp                     fPng_ptr;
     png_infop                       fInfo_ptr;
 
     // These are stored here so they can be used both by normal decoding and scanline decoding.
     SkAutoTUnref<SkColorTable>      fColorTable;    // May be unpremul.
     SkAutoTDelete<SkSwizzler>       fSwizzler;
 
     SkSwizzler::SrcConfig           fSrcConfig;
     const int                       fNumberPasses;
     int                             fBitDepth;
-    AlphaState                      fAlphaState;
 
     bool decodePalette(bool premultiply, int* ctableCount);
     void destroyReadStruct();
 
     typedef SkCodec INHERITED;
 };