Drop background color optimization for composited layers

LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt

Index: LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt
diff --git a/LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt b/LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt
index da2a8450ce03483aa70398a38840d835796c0a2a..e20a928d09ebab0708edde7feb29e9ab28232460 100644
--- a/LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt
+++ b/LayoutTests/compositing/layer-creation/overlap-transformed-3d-expected.txt
@@ -11,6 +11,8 @@ Before:
           (position 108.00 108.00)
           (bounds 100.00 100.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #008000)
           (transform [1.00 0.00 0.00 0.00] [0.00 1.00 0.00 0.00] [0.00 0.00 1.00 0.00] [0.00 0.00 -1.00 1.00])
         )
       )
@@ -31,27 +33,37 @@ After:
           (position 108.00 108.00)
           (bounds 100.00 100.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #008000)
           (transform [0.71 0.71 0.00 0.00] [-0.71 0.71 0.00 0.00] [0.00 0.00 1.00 0.00] [0.00 0.00 -1.00 1.00])
         )
         (GraphicsLayer
           (position 8.00 8.00)
           (bounds 100.00 150.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #808080)
         )
         (GraphicsLayer
           (position 208.00 8.00)
           (bounds 100.00 150.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #808080)
         )
         (GraphicsLayer
           (position 8.00 158.00)
           (bounds 100.00 150.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #808080)
         )
         (GraphicsLayer
           (position 208.00 158.00)
           (bounds 100.00 150.00)
           (contentsOpaque 1)
+          (drawsContent 1)
+          (backgroundColor #808080)
         )
       )
     )