Revert of Fixing libpng transform use (patchset #5 id:80001 of https://codereview.chromium.org/1214203005/)

Reason for revert:
DEPS roll failing

Original issue's description:
> This change:
> - supports kGray correctly
> - avoid extra call to png_get_IHDR by storing the bit depth
> - call transforms as needed
> - checks for tRNS alpha value in RGB and GRAY color types
>
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/9693037fd41b7ce545b44beaa3489dcfd915018c

TBR=scroggo@google.com,msarett@google.com,emmaleer@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1213743004

1 files changed, 2 insertions, 5 deletions

diff --git a/src/codec/SkCodec_libpng.h b/src/codec/SkCodec_libpng.h
index c0fee74e96..a105c3c5e3 100644
--- a/src/codec/SkCodec_libpng.h
+++ b/src/codec/SkCodec_libpng.h
@@ -44,17 +44,14 @@ private:
     SkSwizzler::SrcConfig       fSrcConfig;
     int                         fNumberPasses;
     bool                        fReallyHasAlpha;
-    int                         fBitDepth;
 
-    SkPngCodec(const SkImageInfo&, SkStream*, png_structp, png_infop, int);
+    SkPngCodec(const SkImageInfo&, SkStream*, png_structp, png_infop);
     ~SkPngCodec();
 
-
     // Helper to set up swizzler and color table. Also calls png_read_update_info.
     Result initializeSwizzler(const SkImageInfo& requestedInfo, void* dst,
                               size_t rowBytes, const Options&, SkPMColor*, int* ctableCount);
-
-    // Calls rewindIfNeeded and returns true if the decoder can continue.
+    // Calls rewindIfNeeded, and returns true if the decoder can continue.
     bool handleRewind();
     bool decodePalette(bool premultiply, int bitDepth, int* ctableCount);
     void finish();