Use Shadow DOM to display fallback content for images

LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt

Index: LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt
diff --git a/LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt b/LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt
index f72b6ec6979fb357d3f18718f8a8e4f66c1c3973..1575e4c46916d1e32ae56fd0e0b72d081f9ab63e 100644
--- a/LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt
+++ b/LayoutTests/platform/linux/tables/mozilla/bugs/bug9123-1-expected.txt
@@ -20,7 +20,7 @@ layer at (0,0) size 800x600
             RenderTableCell {TD} at (0,7) size 17x3 [bgcolor=#666666] [border: (1px inset #808080)] [r=0 c=0 rs=1 cs=1]
               RenderImage {IMG} at (1,1) size 15x1
             RenderTableCell {TD} at (17,0) size 764x17 [border: (1px inset #808080)] [r=0 c=1 rs=1 cs=1]
-              RenderImage {IMG} at (1,1) size 110x15
+              RenderBlock {IMG} at (1,1) size 110x15
             RenderTableCell {TD} at (781,7) size 17x3 [bgcolor=#666666] [border: (1px inset #808080)] [r=0 c=2 rs=1 cs=1]
               RenderImage {IMG} at (1,1) size 15x1
           RenderTableRow {TR} at (0,17) size 798x22
@@ -30,7 +30,7 @@ layer at (0,0) size 800x600
               RenderText {#text} at (1,1) size 22x19
                 text run at (1,1) width 22: "that"
             RenderTableCell {TD} at (781,26) size 17x3 [bgcolor=#666666] [border: (1px inset #808080)] [r=1 c=2 rs=1 cs=1]
-              RenderImage {IMG} at (1,1) size 15x1
+              RenderBlock {IMG} at (1,1) size 15x1
       RenderBlock {P} at (0,133) size 800x20
         RenderText {#text} at (20,0) size 734x19
           text run at (20,0) width 247: "Here's the first row in a table on its own. "
@@ -39,11 +39,11 @@ layer at (0,0) size 800x600
         RenderTableSection {TBODY} at (1,1) size 798x17
           RenderTableRow {TR} at (0,0) size 798x17
             RenderTableCell {TD} at (0,7) size 84x3 [bgcolor=#666666] [border: (1px inset #808080)] [r=0 c=0 rs=1 cs=1]
-              RenderImage {IMG} at (1,1) size 15x1
+              RenderBlock {IMG} at (1,1) size 15x1
             RenderTableCell {TD} at (84,0) size 629x17 [border: (1px inset #808080)] [r=0 c=1 rs=1 cs=1]
-              RenderImage {IMG} at (1,1) size 110x15
+              RenderBlock {IMG} at (1,1) size 110x15
             RenderTableCell {TD} at (713,7) size 85x3 [bgcolor=#666666] [border: (1px inset #808080)] [r=0 c=2 rs=1 cs=1]
-              RenderImage {IMG} at (1,1) size 15x1
+              RenderBlock {IMG} at (1,1) size 15x1
       RenderBlock {P} at (0,204) size 800x40
         RenderText {#text} at (20,0) size 748x39
           text run at (20,0) width 268: "Here's the second row in a table on its own. "
@@ -64,3 +64,18 @@ layer at (0,0) size 800x600
           text run at (20,0) width 575: "Note that in Nav4.x, the middle column gets the width of the maximum width cell in the column; "
           text run at (595,0) width 184: "on 5.0, the middle column gets"
           text run at (20,20) width 138: "the opposite treatment."
+layer at (19,78) size 110x15 clip at (20,79) size 108x13 scrollHeight 18
+  RenderBlock {DIV} at (0,0) size 110x15 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16
+layer at (783,104) size 15x4 clip at (784,105) size 13x2 scrollWidth 17 scrollHeight 18
+  RenderBlock {DIV} at (0,0) size 15x4 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16
+layer at (2,178) size 15x4 clip at (3,179) size 13x2 scrollWidth 17 scrollHeight 18
+  RenderBlock {DIV} at (0,0) size 15x4 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16
+layer at (86,171) size 110x15 clip at (87,172) size 108x13 scrollHeight 18
+  RenderBlock {DIV} at (0,0) size 110x15 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16
+layer at (715,178) size 15x4 clip at (716,179) size 13x2 scrollWidth 17 scrollHeight 18
+  RenderBlock {DIV} at (0,0) size 15x4 [border: (1px solid #C0C0C0)]
+    RenderImage {IMG} at (2,2) size 16x16