windowscodecs: Store stream reference in png decoder.

dlls/windowscodecs/pngformat.c

@@ -296,6 +296,7 @@ typedef struct {
     IWICBitmapFrameDecode IWICBitmapFrameDecode_iface;
     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
     LONG ref;
+    IStream *stream;
     png_structp png_ptr;
     png_infop info_ptr;
     png_infop end_info;
@@ -366,6 +367,7 @@ static ULONG WINAPI PngDecoder_Release(IWICBitmapDecoder *iface)
 
     if (ref == 0)
     {
+        IStream_Release(This->stream);
         if (This->png_ptr)
             ppng_destroy_read_struct(&This->png_ptr, &This->info_ptr, &This->end_info);
         This->lock.DebugInfo->Spare[0] = 0;
@@ -605,6 +607,9 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
 
     ppng_read_end(This->png_ptr, This->end_info);
 
+    This->stream = pIStream;
+    IStream_AddRef(This->stream);
+
     This->initialized = TRUE;
 
 end:

dlls/windowscodecs/tests/pngformat.c

@@ -283,6 +283,7 @@ static IWICBitmapDecoder *create_decoder(const void *image_data, UINT image_size
     IWICBitmapDecoder *decoder = NULL;
     IStream *stream;
     GUID format;
+    LONG refcount;
 
     hmem = GlobalAlloc(0, image_size);
     data = GlobalLock(hmem);
@@ -300,7 +301,8 @@ static IWICBitmapDecoder *create_decoder(const void *image_data, UINT image_size
     ok(IsEqualGUID(&format, &GUID_ContainerFormatPng),
        "wrong container format %s\n", wine_dbgstr_guid(&format));
 
-    IStream_Release(stream);
+    refcount = IStream_Release(stream);
+    ok(refcount > 0, "expected stream refcount > 0\n");
 
     return decoder;
 }