quartz: Fix video flickering.

dlls/quartz/tests/videorenderer.c

@@ -2368,7 +2368,7 @@ static void test_video_window(void)
     ok(tid == GetCurrentThreadId(), "Expected tid %#lx, got %#lx.\n", GetCurrentThreadId(), tid);
 
     background = GetClassLongPtrW(hwnd, GCLP_HBRBACKGROUND);
-    todo_wine ok(!background, "Expected NULL brush, got %#Ix\n", background);
+    ok(!background, "Expected NULL brush, got %#Ix\n", background);
 
     hr = IBaseFilter_QueryInterface(filter, &IID_IVideoWindow, (void **)&window);
     ok(hr == S_OK, "Got hr %#lx.\n", hr);

dlls/quartz/window.c

@@ -101,7 +101,6 @@ HRESULT video_window_create_window(struct video_window *window)
 
     winclass.lpfnWndProc = WndProcW;
     winclass.cbWndExtra = sizeof(window);
-    winclass.hbrBackground = GetStockObject(BLACK_BRUSH);
     winclass.lpszClassName = class_name;
     if (!RegisterClassW(&winclass) && GetLastError() != ERROR_CLASS_ALREADY_EXISTS)
     {