Remove png_read_end from SkPngScanlineDecoder

src/codec/SkCodec_libpng.cpp

Index: src/codec/SkCodec_libpng.cpp
diff --git a/src/codec/SkCodec_libpng.cpp b/src/codec/SkCodec_libpng.cpp
index 699ab398d3a36df70cfbbb1c24c96886047d7f3c..c1f0025151fde0f729907bd570a1c2b5f8227b31 100644
--- a/src/codec/SkCodec_libpng.cpp
+++ b/src/codec/SkCodec_libpng.cpp
@@ -601,9 +601,7 @@ public:
         fSrcRow = static_cast<uint8_t*>(fStorage.get());
     }
 
-    ~SkPngScanlineDecoder() {
-        fCodec->finish();
-    }
+    ~SkPngScanlineDecoder() {}

[scroggo, 2015/07/20 20:07:25]

nit: I think you can remove this line completely, and the compiler will generate
the same destructor.

(I was wrong on this in one of Matt's CLs, so I may be wrong here as well...)

 
     SkCodec::Result onGetScanlines(void* dst, int count, size_t rowBytes) override {
         if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) {
@@ -662,9 +660,7 @@ public:
         fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get());
     }
 
-    ~SkPngInterlacedScanlineDecoder() {
-        fCodec->finish();
-    }
+    ~SkPngInterlacedScanlineDecoder() {}

[scroggo, 2015/07/20 20:07:25]

Again, I *think* the compiler will generate the same destructor without this
line.

 
     SkCodec::Result onGetScanlines(void* dst, int count, size_t dstRowBytes) override {
         //rewind stream if have previously called onGetScanlines,