Replace RenderFullScreen with top layer

LayoutTests/fullscreen/full-screen-is-in-top-layer-expected.txt

Index: LayoutTests/fullscreen/full-screen-is-in-top-layer-expected.txt
diff --git a/LayoutTests/fullscreen/full-screen-is-in-top-layer-expected.txt b/LayoutTests/fullscreen/full-screen-is-in-top-layer-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..39a5a0221f5bd1cefec4f30288ecc4d1748c8f50
--- /dev/null
+++ b/LayoutTests/fullscreen/full-screen-is-in-top-layer-expected.txt
@@ -0,0 +1,18 @@
+layer at (0,0) size 800x600
+  RenderView at (0,0) size 800x600
+layer at (0,0) size 800x42
+  RenderBlock {HTML} at (0,0) size 800x42
+    RenderBody {BODY} at (8,8) size 784x26
+      RenderButton {BUTTON} at (2,2) size 92x22 [bgcolor=#C0C0C0] [border: (2px outset #C0C0C0)]
+        RenderBlock (anonymous) at (8,3) size 76x16
+          RenderText {#text} at (0,0) size 76x16
+            text run at (0,0) width 76: "Go fullscreen"
+      RenderText {#text} at (0,0) size 0x0
+      RenderText {#text} at (0,0) size 0x0
+layer at (0,0) size 800x600
+  RenderBlock (positioned) at (0,0) size 800x600 [bgcolor=#008000]
+layer at (100,100) size 600x400
+  RenderBlock (positioned) {DIV} at (100,100) size 600x400 [bgcolor=#FFFF00]
+    RenderText {#text} at (0,0) size 600x39
+      text run at (0,0) width 600: "Test that fullscreen elements are in the top layer. The test passes if you see a green backdrop behind"
+      text run at (0,20) width 147: "this box when fullscreen."