winegstreamer: Implement Flush for WMV decoder DMO.

dlls/mf/tests/transform.c

@@ -6392,10 +6392,8 @@ static void test_wmv_decoder_media_object(void)
     hr = IMediaObject_ProcessInput(media_object, 0, &input_media_buffer->IMediaBuffer_iface, 0, 0, 0);
     ok(hr == S_OK, "ProcessInput returned %#lx.\n", hr);
     hr = IMediaObject_Flush(media_object);
-    todo_wine
     ok(hr == S_OK, "Flush returned %#lx.\n", hr);
     hr = IMediaObject_Flush(media_object);
-    todo_wine
     ok(hr == S_OK, "Flush returned %#lx.\n", hr);
     output_media_buffer->length = 0;
     output_data_buffer.pBuffer = &output_media_buffer->IMediaBuffer_iface;
@@ -6405,7 +6403,6 @@ static void test_wmv_decoder_media_object(void)
     hr = IMediaObject_ProcessOutput(media_object, 0, 1, &output_data_buffer, &status);
     todo_wine
     ok(hr == S_FALSE, "ProcessOutput returned %#lx.\n", hr);
-    todo_wine
     ok(output_media_buffer->length == 0, "Unexpected length %#lx.\n", output_media_buffer->length);
 
     /* Test ProcessOutput with setting framerate. */

dlls/winegstreamer/wmv_decoder.c

@@ -657,8 +657,17 @@ static HRESULT WINAPI media_object_SetInputMaxLatency(IMediaObject *iface, DWORD
 
 static HRESULT WINAPI media_object_Flush(IMediaObject *iface)
 {
-    FIXME("iface %p stub!\n", iface);
-    return E_NOTIMPL;
+    struct wmv_decoder *decoder = impl_from_IMediaObject(iface);
+    HRESULT hr;
+
+    TRACE("iface %p.\n", iface);
+
+    if (FAILED(hr = wg_transform_flush(decoder->wg_transform)))
+        return hr;
+
+    wg_sample_queue_flush(decoder->wg_sample_queue, TRUE);
+
+    return S_OK;
 }
 
 static HRESULT WINAPI media_object_Discontinuity(IMediaObject *iface, DWORD index)