amstream: Check purpose id in AddMediaStream.

dlls/amstream/amstream.c

@@ -326,6 +326,9 @@ static HRESULT WINAPI IAMMultiMediaStreamImpl_AddMediaStream(IAMMultiMediaStream
 
     FIXME("(%p/%p)->(%p,%s,%x,%p) partial stub!\n", This, iface, pStreamObject, debugstr_guid(PurposeId), dwFlags, ppNewStream);
 
+    if (!IsEqualGUID(PurposeId, &MSPID_PrimaryVideo) && !IsEqualGUID(PurposeId, &MSPID_PrimaryAudio))
+        return MS_E_PURPOSEID;
+
     hr = mediastream_create((IMultiMediaStream*)iface, PurposeId, This->StreamType, &pStream);
     if (SUCCEEDED(hr))
     {

dlls/amstream/tests/amstream.c

@@ -224,7 +224,7 @@ static void test_media_streams(void)
     hr = IAMMultiMediaStream_GetMediaStream(pams, &IID_IUnknown, &dummy_stream);
     ok(hr == MS_E_NOSTREAM, "IAMMultiMediaStream_GetMediaStream returned: %x\n", hr);
     hr = IAMMultiMediaStream_AddMediaStream(pams, NULL, &IID_IUnknown, 0, NULL);
-    todo_wine ok(hr == MS_E_PURPOSEID, "IAMMultiMediaStream_AddMediaStream returned: %x\n", hr);
+    ok(hr == MS_E_PURPOSEID, "IAMMultiMediaStream_AddMediaStream returned: %x\n", hr);
 
     if (video_stream)
     {