Nit: less specific cast

Change-Id: I06dc5c8977761e32c468fb43e91739d872f2a6aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1900925
Commit-Queue: Aleks Totic <atotic@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Auto-Submit: Aleks Totic <atotic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713510}

third_party/blink/renderer/core/paint/ng/ng_box_fragment_painter.cc

@@ -635,7 +635,7 @@ void NGBoxFragmentPainter::PaintBoxDecorationBackground(
     paint_rect.size = box_fragment_.Size();
     if (layout_object.IsTableCell()) {
       paint_rect.size =
-          PhysicalSize(To<LayoutTableCell>(layout_object).PixelSnappedSize());
+          PhysicalSize(ToLayoutBox(layout_object).PixelSnappedSize());
     }
     background_client = &GetDisplayItemClient();
   }