Drop background color optimization for composited layers

LayoutTests/compositing/rtl/rtl-fixed-expected.txt

Index: LayoutTests/compositing/rtl/rtl-fixed-expected.txt
diff --git a/LayoutTests/compositing/rtl/rtl-fixed-expected.txt b/LayoutTests/compositing/rtl/rtl-fixed-expected.txt
index 684dc550c9f8b10c286017ed840ec25e80088aee..8b3d0e4de5d525bf233b26885379af883434b06d 100644
--- a/LayoutTests/compositing/rtl/rtl-fixed-expected.txt
+++ b/LayoutTests/compositing/rtl/rtl-fixed-expected.txt
@@ -10,6 +10,8 @@
           (position 50.00 50.00)
           (bounds 100.00 100.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #008000)
         )
       )
     )