Get rid of leaks in SkCodec::NewFromStream.

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 328 matching lines @@
     if (png_ptrp) {
         *png_ptrp = png_ptr;
     }
     if (info_ptrp) {
         *info_ptrp = info_ptr;
     }
     return true;
 }
 
 SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
+    SkAutoTDelete<SkStream> streamDeleter(stream);
     png_structp png_ptr;
     png_infop info_ptr;
     SkImageInfo imageInfo;
     if (read_header(stream, &png_ptr, &info_ptr, &imageInfo)) {
-        return SkNEW_ARGS(SkPngCodec, (imageInfo, stream, png_ptr, info_ptr));
+        return SkNEW_ARGS(SkPngCodec, (imageInfo, streamDeleter.detach(), png_ptr, info_ptr));
     }
     return NULL;
 }
 
 #define INVALID_NUMBER_PASSES -1
 SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream,
                        png_structp png_ptr, png_infop info_ptr)
     : INHERITED(info, stream)
     , fPng_ptr(png_ptr)
     , fInfo_ptr(info_ptr)
@@ skipping 273 matching lines @@
 
     SkASSERT(fNumberPasses != INVALID_NUMBER_PASSES);
     if (fNumberPasses > 1) {
         // We cannot efficiently do scanline decoding.
         return NULL;
     }
 
     return SkNEW_ARGS(SkPngScanlineDecoder, (dstInfo, this));
 }