windowscodecs: Store stream reference in gif decoder.

dlls/windowscodecs/gifformat.c

@@ -578,6 +578,7 @@ static HRESULT create_metadata_reader(const void *data, int data_size,
 typedef struct {
     IWICBitmapDecoder IWICBitmapDecoder_iface;
     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
+    IStream *stream;
     BYTE LSD_data[13]; /* Logical Screen Descriptor */
     LONG ref;
     BOOL initialized;
@@ -1054,6 +1055,7 @@ static ULONG WINAPI GifDecoder_Release(IWICBitmapDecoder *iface)
 
     if (ref == 0)
     {
+        IStream_Release(This->stream);
         This->lock.DebugInfo->Spare[0] = 0;
         DeleteCriticalSection(&This->lock);
         DGifCloseFile(This->gif);
@@ -1141,6 +1143,9 @@ static HRESULT WINAPI GifDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
     IStream_Seek(pIStream, seek, STREAM_SEEK_SET, NULL);
     IStream_Read(pIStream, This->LSD_data, sizeof(This->LSD_data), NULL);
 
+    This->stream = pIStream;
+    IStream_AddRef(This->stream);
+
     This->initialized = TRUE;
 
     LeaveCriticalSection(&This->lock);

dlls/windowscodecs/tests/gifformat.c

@@ -67,6 +67,7 @@ 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);
@@ -84,7 +85,8 @@ static IWICBitmapDecoder *create_decoder(const void *image_data, UINT image_size
     ok(IsEqualGUID(&format, &GUID_ContainerFormatGif),
        "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;
 }