uxtheme: Handle BT_NONE in GetThemeBackgroundRegion().

dlls/uxtheme/draw.c

@@ -2063,8 +2063,12 @@ HRESULT WINAPI GetThemeBackgroundRegion(HTHEME hTheme, HDC hdc, int iPartId,
         if(!*pRegion)
             hr = HRESULT_FROM_WIN32(GetLastError());
     }
+    else if (bgtype == BT_NONE)
+    {
+        hr = E_UNEXPECTED;
+    }
     else {
-        FIXME("Unknown background type\n");
+        FIXME("Unknown background type %d\n", bgtype);
         /* This should never happen, and hence I don't know what to return */
         hr = E_FAIL;
     }

dlls/uxtheme/tests/system.c

@@ -2425,7 +2425,6 @@ static void test_GetThemeBackgroundRegion(void)
     SetRect(&rect, 0, 0, 10, 10);
     region = (HRGN)0xdeadbeef;
     hr = GetThemeBackgroundRegion(htheme, NULL, RP_BAND, 0, &rect, &region);
-    todo_wine
     ok(hr == E_UNEXPECTED || broken(hr == S_OK) /* < Win10 */, "Got unexpected hr %#lx.\n", hr);
     ok(region == (HRGN)0xdeadbeef, "Got unexpected region.\n");