Use Shadow DOM to display fallback content for images

LayoutTests/fast/table/008-expected.txt

Index: LayoutTests/fast/table/008-expected.txt
diff --git a/LayoutTests/fast/table/008-expected.txt b/LayoutTests/fast/table/008-expected.txt
index 83c15dc2072a3b3e70d89be379b01110c2b2303b..dbf4b50752e7defcdd052334922cedaf4ca65570 100644
--- a/LayoutTests/fast/table/008-expected.txt
+++ b/LayoutTests/fast/table/008-expected.txt
@@ -7,5 +7,11 @@ layer at (0,0) size 800x600
         RenderTableSection {TBODY} at (0,0) size 140x138
           RenderTableRow {TR} at (0,0) size 140x138
             RenderTableCell {TD} at (0,0) size 140x138 [r=0 c=0 rs=1 cs=1]
-              RenderImage {IMG} at (0,0) size 129x104 [border: (5px solid #000000)]
-              RenderImage {IMG} at (0,104) size 129x34 [border: (5px solid #000000)]
+              RenderBlock {IMG} at (0,0) size 129x104 [border: (5px solid #000000)]
+              RenderBlock {IMG} at (0,104) size 129x34 [border: (5px solid #000000)]
+layer at (13,13) size 119x94 clip at (14,14) size 117x92
+  RenderBlock {DIV} at (5,5) size 119x94 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16
+layer at (13,117) size 119x24 clip at (14,118) size 117x22
+  RenderBlock {DIV} at (5,5) size 119x24 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16