winegstreamer: Implement Discontinuity for WMV decoder DMO.

dlls/mf/tests/transform.c

@@ -5596,13 +5596,10 @@ static void test_wmv_decoder_media_object(void)
 
     /* Test Discontinuity.  */
     hr = IMediaObject_Discontinuity(media_object, 0xdeadbeef);
-    todo_wine
     ok(hr == DMO_E_INVALIDSTREAMINDEX, "Discontinuity returned %#lx.\n", hr);
     hr = IMediaObject_Discontinuity(media_object, 0);
-    todo_wine
     ok(hr == S_OK, "Discontinuity returned %#lx.\n", hr);
     hr = IMediaObject_Discontinuity(media_object, 0);
-    todo_wine
     ok(hr == S_OK, "Discontinuity returned %#lx.\n", hr);
     hr = IMediaObject_GetInputStatus(media_object, 0, &status);
     ok(hr == S_OK, "GetInputStatus returned %#lx.\n", hr);

dlls/winegstreamer/wmv_decoder.c

@@ -662,8 +662,12 @@ static HRESULT WINAPI media_object_Flush(IMediaObject *iface)
 
 static HRESULT WINAPI media_object_Discontinuity(IMediaObject *iface, DWORD index)
 {
-    FIXME("iface %p, index %lu stub!\n", iface, index);
-    return E_NOTIMPL;
+    TRACE("iface %p, index %lu.\n", iface, index);
+
+    if (index > 0)
+        return DMO_E_INVALIDSTREAMINDEX;
+
+    return S_OK;
 }
 
 static HRESULT WINAPI media_object_AllocateStreamingResources(IMediaObject *iface)