evr: Respond to IMFVideoMixerControl in mixer's GetService().

dlls/evr/mixer.c

@@ -1021,7 +1021,9 @@ static HRESULT WINAPI video_mixer_getservice_GetService(IMFGetService *iface, RE
     {
         if (IsEqualIID(riid, &IID_IMFVideoMixerBitmap) ||
                 IsEqualIID(riid, &IID_IMFVideoProcessor) ||
-                IsEqualIID(riid, &IID_IMFVideoPositionMapper))
+                IsEqualIID(riid, &IID_IMFVideoPositionMapper) ||
+                IsEqualIID(riid, &IID_IMFVideoMixerControl) ||
+                IsEqualIID(riid, &IID_IMFVideoMixerControl2))
         {
             return IMFGetService_QueryInterface(iface, riid, obj);
         }

dlls/evr/tests/evr.c

@@ -450,6 +450,10 @@ static void test_default_mixer(void)
     hr = IMFGetService_GetService(gs, &MR_VIDEO_MIXER_SERVICE, &IID_IMFVideoProcessor, (void **)&processor);
     ok(hr == S_OK, "Unexpected hr %#x.\n", hr);
 
+    hr = IMFGetService_GetService(gs, &MR_VIDEO_MIXER_SERVICE, &IID_IMFVideoMixerControl, (void **)&unk);
+    ok(hr == S_OK, "Unexpected hr %#x.\n", hr);
+    IUnknown_Release(unk);
+
     hr = IMFVideoProcessor_GetBackgroundColor(processor, NULL);
     ok(hr == E_POINTER, "Unexpected hr %#x.\n", hr);