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

LayoutTests/platform/linux/svg/batik/text/textStyles-expected.txt

 layer at (0,0) size 800x600
   RenderView at (0,0) size 800x600
 layer at (0,0) size 450x500
   RenderSVGRoot {svg} at (0,0) size 448x498
-    RenderSVGHiddenContainer {defs} at (0,0) size 0x0
+    LayoutSVGHiddenContainer {defs} at (0,0) size 0x0
       LayoutSVGText {text} at (-21,-15) size 42x19 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 42x19
           chunk 1 (middle anchor) text run 1 at (-21.00,0.00) startOffset 0 endOffset 6 width 42.00: "sample"
     LayoutSVGContainer {g} at (31,36) size 383x392
       LayoutSVGText {text} at (136,36) size 178x17 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 178x17
           chunk 1 (middle anchor) text run 1 at (136.00,50.00) startOffset 0 endOffset 26 width 178.00: "Text Font Faces and Styles"
       LayoutSVGText {text} at (184,65) size 82x12 contains 1 chunk(s)
         LayoutSVGInlineText {#text} at (0,0) size 82x12
           chunk 1 (middle anchor) text run 1 at (184.00,75.00) startOffset 0 endOffset 19 width 82.00: "Standard Font Faces"
@@ skipping 138 matching lines @@
             chunk 1 (middle anchor) text run 1 at (-17.00,15.00) startOffset 0 endOffset 6 width 34.00: "Impact"
       LayoutSVGContainer {g} at (286,413) size 128x15 [transform={m=((1.00,0.00)(0.00,1.00)) t=(350.00,410.00)}]
         LayoutSVGText {text}
         LayoutSVGText {text} at (-64,3) size 128x15 contains 1 chunk(s)
           LayoutSVGInlineText {#text} at (0,0) size 128x15
             chunk 1 (middle anchor) text run 1 at (-64.00,15.00) startOffset 0 endOffset 25 width 128.00: "AvantGarde (line-through)"
     LayoutSVGContainer {use} at (0,0) size 448x498
       LayoutSVGContainer {g} at (0,0) size 448x498
         LayoutSVGRect {rect} at (0,0) size 448x498 [stroke={[type=SOLID] [color=#000000]}] [x=1.00] [y=1.00] [width=446.00] [height=496.00]
         LayoutSVGContainer {g} at (418,466) size 28x30 [transform={m=((1.00,0.00)(0.00,1.00)) t=(418.00,467.00)}]
-          RenderSVGViewportContainer {svg} at (418,466) size 28x30
+          LayoutSVGViewportContainer {svg} at (418,466) size 28x30
             LayoutSVGPath {path} at (418,468) size 14x19 [fill={[type=SOLID] [color=#6666FF]}] [data="M 172 44 C 137 60 31 135 11 199 C 3 226 33 247 55 232 C 14 306 -1 332 0 356 C 0 370 13 398 44 383 C 52 379 79 358 96 342 C 110 341 120 331 138 314 C 155 328 174 324 190 307 C 212 309 272 229 234 199 C 231 175 204 162 181 181 C 175 179 168 180 163 182 C 185 147 206 100 212 77 C 219 47 188 36 172 44 Z"]
             LayoutSVGPath {path} at (432,466) size 14x17 [fill={[type=SOLID] [color=#FF0000]}] [data="M 400 0 C 382 3 351 31 351 31 C 322 54 308 89 323 126 C 310 140 294 170 294 193 C 294 221 314 245 344 222 C 351 230 365 238 381 227 C 376 256 384 275 407 276 C 408 286 420 307 443 293 C 459 283 501 254 522 237 C 547 214 547 143 504 148 C 537 89 501 52 477 64 C 467 68 431 89 425 94 C 424 87 420 82 414 80 C 436 45 436 -5 401 0 Z"]
             LayoutSVGPath {path} at (425,484) size 16x12 [fill={[type=SOLID] [color=#33CC33]}] [data="M 275 353 C 229 365 187 396 161 444 C 152 460 167 481 186 477 C 172 501 146 544 171 558 C 199 574 223 550 231 543 C 249 564 281 553 312 526 C 353 540 380 524 415 473 C 423 461 445 430 445 408 C 445 392 430 378 410 387 C 409 375 401 349 357 368 C 347 362 326 363 303 385 C 308 375 300 347 275 353 Z"]