Remove png_read_end from SkPngScanlineDecoder

src/codec/SkCodec_libpng.cpp

 /*
  * 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_libpng.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 558 matching lines @@
         for (int y = 0; y < requestedInfo.height(); y++) {
             png_read_rows(fPng_ptr, &srcRow, png_bytepp_NULL, 1);
             fReallyHasAlpha |= !SkSwizzler::IsOpaque(fSwizzler->next(srcRow));
         }
     }
 
     // FIXME: do we need substituteTranspColor? Note that we cannot do it for
     // scanline decoding, but we could do it here. Alternatively, we could do
     // it as we go, instead of in post-processing like SkPNGImageDecoder.
 
-    this->finish();
+    if (setjmp(png_jmpbuf(fPng_ptr))) {
+        // We've already read all the scanlines. This is a success.
+        return kSuccess;
+    }
+
+    // read rest of file, and get additional comment and time chunks in info_ptr
+    png_read_end(fPng_ptr, fInfo_ptr);
     return kSuccess;
 }
 
-void SkPngCodec::finish() {
-    if (setjmp(png_jmpbuf(fPng_ptr))) {
-        // We've already read all the scanlines. This is a success.
-        return;
-    }
-    // FIXME: Is this necessary?
-    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
-    png_read_end(fPng_ptr, fInfo_ptr);
-}
-
 class SkPngScanlineDecoder : public SkScanlineDecoder {
 public:
     SkPngScanlineDecoder(const SkImageInfo& dstInfo, SkPngCodec* codec)
         : INHERITED(dstInfo)
         , fCodec(codec)
         , fHasAlpha(false)
     {
         fStorage.reset(dstInfo.width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig));
         fSrcRow = static_cast<uint8_t*>(fStorage.get());
     }
 
-    ~SkPngScanlineDecoder() {
-        fCodec->finish();
-    }
-
     SkCodec::Result onGetScanlines(void* dst, int count, size_t rowBytes) override {
         if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) {
             SkCodecPrintf("setjmp long jump!\n");
             return SkCodec::kInvalidInput;
         }
 
         for (int i = 0; i < count; i++) {
             png_read_rows(fCodec->fPng_ptr, &fSrcRow, png_bytepp_NULL, 1);
             fCodec->fSwizzler->setDstRow(dst);
             fHasAlpha |= !SkSwizzler::IsOpaque(fCodec->fSwizzler->next(fSrcRow));
@@ skipping 37 matching lines @@
         , fCodec(codec)
         , fHasAlpha(false)
         , fCurrentRow(0)
         , fHeight(dstInfo.height())
     {
         fSrcRowBytes = dstInfo.width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig);
         fGarbageRow.reset(fSrcRowBytes);
         fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get());
     }
 
-    ~SkPngInterlacedScanlineDecoder() {
-        fCodec->finish();
-    }
-
     SkCodec::Result onGetScanlines(void* dst, int count, size_t dstRowBytes) override {
         //rewind stream if have previously called onGetScanlines, 
         //since we need entire progressive image to get scanlines
         if (!fCodec->handleRewind()) {
             return SkCodec::kCouldNotRewind;
         }
         if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) {
             SkCodecPrintf("setjmp long jump!\n");
             return SkCodec::kInvalidInput;
         }
@@ skipping 81 matching lines @@
 
     SkASSERT(codec->fNumberPasses != INVALID_NUMBER_PASSES);
     if (codec->fNumberPasses > 1) {
         // interlaced image
         return SkNEW_ARGS(SkPngInterlacedScanlineDecoder, (dstInfo, codec.detach()));
     }
 
     return SkNEW_ARGS(SkPngScanlineDecoder, (dstInfo, codec.detach()));
 }