Move the SVG container code from rendering/svg to layout/svg.

LayoutTests/svg/custom/use-symbol-overflow-expected.txt

Index: LayoutTests/svg/custom/use-symbol-overflow-expected.txt
diff --git a/LayoutTests/svg/custom/use-symbol-overflow-expected.txt b/LayoutTests/svg/custom/use-symbol-overflow-expected.txt
index 36c7494d233dcd89cca2e2e17a531ba98d75eee5..f00b38e97ac3d60f1c414e1153300171612c451d 100644
--- a/LayoutTests/svg/custom/use-symbol-overflow-expected.txt
+++ b/LayoutTests/svg/custom/use-symbol-overflow-expected.txt
@@ -2,9 +2,9 @@ layer at (0,0) size 800x600
   RenderView at (0,0) size 800x600
 layer at (0,0) size 800x600
   RenderSVGRoot {svg} at (0,0) size 100x100
-    RenderSVGHiddenContainer {defs} at (0,0) size 0x0
-      RenderSVGHiddenContainer {symbol} at (0,0) size 0x0
+    LayoutSVGHiddenContainer {defs} at (0,0) size 0x0
+      LayoutSVGHiddenContainer {symbol} at (0,0) size 0x0
         LayoutSVGRect {rect} at (0,0) size 50x50 [fill={[type=SOLID] [color=#008000]}] [x=-50.00] [y=-50.00] [width=100.00] [height=100.00]
     LayoutSVGContainer {use} at (0,0) size 100x100 [transform={m=((1.00,0.00)(0.00,1.00)) t=(50.00,50.00)}]
-      RenderSVGViewportContainer {svg} at (0,0) size 100x100
+      LayoutSVGViewportContainer {svg} at (0,0) size 100x100
         LayoutSVGRect {rect} at (0,0) size 100x100 [fill={[type=SOLID] [color=#008000]}] [x=-50.00] [y=-50.00] [width=100.00] [height=100.00]