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

LayoutTests/platform/win-xp/svg/carto.net/textbox-expected.txt

 layer at (0,0) size 800x600
   RenderView at (0,0) size 800x600
 layer at (0,0) size 800x600
   RenderSVGRoot {svg} at (0,0) size 800x600
     LayoutSVGRect {rect} at (0,0) size 800x600 [fill={[type=SOLID] [color=#FFFFFF]}] [x=-1000.00] [y=-1000.00] [width=3000.00] [height=3000.00]
     LayoutSVGContainer {g} at (77,77) size 158x26
       LayoutSVGContainer {g} at (77,77) size 158x26
         LayoutSVGRect {rect} at (77,77) size 158x26 [stroke={[type=SOLID] [color=#696969] [stroke width=1.50]}] [fill={[type=SOLID] [color=#FFFFFF]}] [x=100.00] [y=100.00] [width=200.00] [height=30.00]
-        RenderSVGViewportContainer {svg} at (77,84) size 2x14
+        LayoutSVGViewportContainer {svg} at (77,84) size 2x14
           LayoutSVGContainer {g} at (77,84) size 2x14
             LayoutSVGText {text}
             LayoutSVGPath {line} at (77,84) size 2x14 [stroke={[type=SOLID] [color=#FF0000] [stroke width=1.50]}] [fill={[type=SOLID] [color=#000000]}] [x1=100.00] [y1=125.00] [x2=100.00] [y2=108.50]
     LayoutSVGContainer {g} at (77,22) size 49x26
       LayoutSVGContainer {g} at (77,22) size 49x26
         LayoutSVGRect {rect} at (77,22) size 49x26 [stroke={[type=SOLID] [color=#696969] [stroke width=1.50]}] [fill={[type=SOLID] [color=#FFFFFF]}] [x=100.00] [y=30.00] [width=60.00] [height=30.00]
-        RenderSVGViewportContainer {svg} at (77,29) size 18x15
+        LayoutSVGViewportContainer {svg} at (77,29) size 18x15
           LayoutSVGContainer {g} at (77,29) size 18x15
             LayoutSVGText {text} at (105,37) size 16x19 contains 1 chunk(s)
               LayoutSVGInlineText {#text} at (0,0) size 16x18
                 chunk 1 text run 1 at (105.00,52.00) startOffset 0 endOffset 2 width 15.36: "50"
             LayoutSVGPath {line} at (77,30) size 2x13 [stroke={[type=SOLID] [color=#FF0000] [stroke width=1.50]}] [fill={[type=SOLID] [color=#000000]}] [x1=100.00] [y1=55.00] [x2=100.00] [y2=38.50]
     LayoutSVGContainer {g} at (77,233) size 323x26 [transform={m=((1.00,0.00)(0.00,1.00)) t=(100.00,300.00)}]
       LayoutSVGContainer {g} at (77,233) size 323x26
         LayoutSVGRect {rect} at (77,233) size 182x26 [stroke={[type=SOLID] [color=#696969] [stroke width=1.50]}] [fill={[type=SOLID] [color=#FFFFFF]}] [x=0.00] [y=0.00] [width=230.00] [height=30.00]
-        RenderSVGViewportContainer {svg} at (77,240) size 323x15
+        LayoutSVGViewportContainer {svg} at (77,240) size 323x15
           LayoutSVGContainer {g} at (77,240) size 323x15
             LayoutSVGText {text} at (5,7) size 406x19 contains 1 chunk(s)
               LayoutSVGInlineText {#text} at (0,0) size 406x18
                 chunk 1 text run 1 at (5.00,22.00) startOffset 0 endOffset 66 width 405.76: "This is a transformed textbox with a very, very, very long content"
             LayoutSVGPath {line} at (77,241) size 2x13 [stroke={[type=SOLID] [color=#FF0000] [stroke width=1.50]}] [fill={[type=SOLID] [color=#000000]}] [x1=0.00] [y1=25.00] [x2=0.00] [y2=8.50]
     LayoutSVGContainer {g} at (78,28) size 659x258
       LayoutSVGText {text} at (100,215) size 66x19 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 66x18
           chunk 1 text run 1 at (100.00,230.00) startOffset 0 endOffset 10 width 65.28: "ResultText"
       LayoutSVGText {text} at (170,35) size 312x19 contains 1 chunk(s)
@@ skipping 10 matching lines @@
             chunk 1 text run 1 at (350.00,338.00) startOffset 0 endOffset 38 width 221.44: "and accepts all characters (up to 300)"
       LayoutSVGText {text} at (620,300) size 297x19 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 297x18
           chunk 1 text run 1 at (620.00,315.00) startOffset 0 endOffset 51 width 296.96: "Click on this text to reset content of textbox nr 3"
       LayoutSVGText {text} at (620,323) size 323x19 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 323x18
           chunk 1 text run 1 at (620.00,338.00) startOffset 0 endOffset 54 width 322.56: "Click on this text to randomly reposition textbox nr 3"
       LayoutSVGText {text} at (620,346) size 296x19 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 296x18
           chunk 1 text run 1 at (620.00,361.00) startOffset 0 endOffset 50 width 295.68: "Click on this text to randomly resize textbox nr 3"