Move and rename RenderBR to LayoutBR.

LayoutTests/platform/win/svg/wicd/rightsizing-grid-expected.txt

 layer at (0,0) size 800x600 clip at (0,0) size 785x600 scrollHeight 1435
   RenderView at (0,0) size 800x600
 layer at (0,0) size 785x1435 backgroundClip at (0,0) size 785x600 clip at (0,0) size 785x600 outlineClip at (0,0) size 785x600
   RenderBlock {html} at (0,0) size 785x1435.14
     RenderBody {body} at (8,8) size 769x0
       RenderBlock (floating) {div} at (0,0) size 769x1427.14
         RenderBlock {h1} at (0,21.44) size 769x37
           RenderText {#text} at (0,0) size 443x36
             text run at (0,0) width 443: "SVG grid with percentage width"
         RenderBlock {h4} at (0,79.88) size 769x18
           RenderText {#text} at (0,0) size 149x17
             text run at (0,0) width 149: "WICD Core 1.0 #20-3"
         RenderBlock {p} at (0,119.14) size 769x0
           RenderBlock (floating) {div} at (256.30,128) size 256.30x448
-            RenderBR {br} at (256,0) size 1x17
+            LayoutBR {br} at (256,0) size 1x17
           RenderBlock (floating) {div} at (512.59,128) size 256.30x448
           RenderBlock (floating) {div} at (384.50,704) size 384.50x192
           RenderBlock (floating) {div} at (0,896) size 384.50x192
           RenderBlock (floating) {div} at (384.50,1024) size 384.50x128
         RenderBlock {p} at (0,119.14) size 769x594 [color=#FFFFFF]
-          RenderBR {br} at (769,0) size 0x17
+          LayoutBR {br} at (769,0) size 0x17
           RenderText {#text} at (640,576) size 9x17
             text run at (640,576) width 9: ".."
         RenderBlock {p} at (0,729.14) size 769x578
           RenderText {#text} at (640,0) size 763x577
             text run at (640,0) width 123: "Above, you should"
             text run at (640,18) width 100: "see a grid of 17"
             text run at (640,36) width 69: "SVG child"
             text run at (640,54) width 107: "elements sticked"
             text run at (640,72) width 107: "together to build"
             text run at (0,542) width 124: "one rectangle grid. "
@@ skipping 12 matching lines @@
           RenderInline {a} at (0,0) size 22x17 [color=#0000EE]
             RenderText {#text} at (465,560) size 22x17
               text run at (465,560) width 22: "big"
           RenderText {#text} at (486,560) size 5x17
             text run at (486,560) width 5: "."
         RenderBlock {p} at (0,1323.14) size 769x36
           RenderText {#text} at (0,0) size 763x35
             text run at (0,0) width 763: "The test is successful, if all SVG elements resize exacly dependend on the width of the browser window, but keep their"
             text run at (0,18) width 636: "aspect ratio and relative position. The complete grid should always show a perfect rectangle object."
         RenderBlock {p} at (0,1375.14) size 769x36
-          RenderBR {br} at (0,0) size 0x17
+          LayoutBR {br} at (0,0) size 0x17
           RenderInline {a} at (0,0) size 33x17 [color=#0000EE]
             RenderText {#text} at (0,18) size 33x17
               text run at (0,18) width 33: "Back"
 layer at (8,127) size 385x128
   LayoutEmbeddedObject {object} at (0,0) size 384.50x128
     layer at (0,0) size 385x128
       RenderView at (0,0) size 385x128
     layer at (0,0) size 385x128
       RenderSVGRoot {svg} at (0,0) size 385x128
         LayoutSVGHiddenContainer {defs} at (0,0) size 0x0
@@ skipping 248 matching lines @@
     layer at (0,0) size 96x128
       RenderSVGRoot {svg} at (0,0) size 96x128
         LayoutSVGHiddenContainer {defs} at (0,0) size 0x0
           LayoutSVGResourceLinearGradient {linearGradient} [id="surface"] [gradientUnits=objectBoundingBox] [start=(1,0)] [end=(1,1)]
             RenderSVGGradientStop {stop} [offset=0.00] [color=#FFFFFF]
             RenderSVGGradientStop {stop} [offset=1.00] [color=#FFEEAA]
         LayoutSVGRect {rect} at (0,0) size 96x128 [stroke={[type=SOLID] [color=#FFCC33] [stroke width=2.00]}] [fill={[type=LINEAR-GRADIENT] [id="surface"]}] [x=1.00] [y=1.00] [width=28.00] [height=38.00]
         LayoutSVGText {text} at (8,9) size 14x23 contains 1 chunk(s)
           LayoutSVGInlineText {#text} at (0,0) size 13x23
             chunk 1 (middle anchor) text run 1 at (8.89,27.00) startOffset 0 endOffset 1 width 12.22: "T"