Move and rename RenderBR to LayoutBR.

LayoutTests/platform/linux/media/video-zoom-expected.txt

Index: LayoutTests/platform/linux/media/video-zoom-expected.txt
diff --git a/LayoutTests/platform/linux/media/video-zoom-expected.txt b/LayoutTests/platform/linux/media/video-zoom-expected.txt
index 3e890bf297064cca95d6c28d0189c8f90922d689..63e17b5d5d7c25e002c0b8a84283bd9366a2e72e 100644
--- a/LayoutTests/platform/linux/media/video-zoom-expected.txt
+++ b/LayoutTests/platform/linux/media/video-zoom-expected.txt
@@ -9,14 +9,14 @@ layer at (0,0) size 785x850 backgroundClip at (0,0) size 785x600 clip at (0,0) s
       RenderBlock (anonymous) at (0,36) size 769x373
         RenderText {#text} at (0,353) size 4x19
           text run at (0,353) width 4: " "
-        RenderBR {BR} at (492,368) size 0x0
+        LayoutBR {BR} at (492,368) size 0x0
       RenderBlock {P} at (0,425) size 769x20
         RenderText {#text} at (0,0) size 287x19
           text run at (0,0) width 287: "150% zoom, without width and height attributes"
       RenderBlock (anonymous) at (0,461) size 769x373
         RenderText {#text} at (0,353) size 4x19
           text run at (0,353) width 4: " "
-        RenderBR {BR} at (492,368) size 0x0
+        LayoutBR {BR} at (492,368) size 0x0
 layer at (12,44) size 488x368
   LayoutVideo {VIDEO} at (4,0) size 488x368 [border: (4px solid #FF0000)]
 layer at (12,469) size 488x368 backgroundClip at (0,0) size 785x600 clip at (0,0) size 785x600 outlineClip at (0,0) size 785x600