The HTML parser should lazy attach.

LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt

Index: LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt
diff --git a/LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt b/LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt
index ca4177797541387978ba895054b61501cfb1710e..78fbebf4687dce9d9531e2a9b4c28efa070f3d74 100644
--- a/LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt
+++ b/LayoutTests/platform/win/fast/forms/textarea-scroll-height-expected.txt
@@ -10,44 +10,59 @@ layer at (0,0) size 800x600
 layer at (8,8) size 200x200 clip at (9,9) size 183x198 scrollHeight 386
   RenderTextControl {TEXTAREA} at (0,0) size 200x200 [bgcolor=#FFFFFF] [border: (1px solid #000000)]
     RenderBlock {DIV} at (3,3) size 181x384
-      RenderText {#text} at (0,0) size 128x368
+      RenderText {#text} at (0,0) size 128x16
         text run at (0,0) width 128: "Lots of content."
-        text run at (128,0) width 0: " "
+      RenderBR {BR} at (128,12) size 0x0
+      RenderText {#text} at (0,16) size 128x16
         text run at (0,16) width 128: "Lots of content."
-        text run at (128,16) width 0: " "
+      RenderBR {BR} at (128,28) size 0x0
+      RenderText {#text} at (0,32) size 128x16
         text run at (0,32) width 128: "Lots of content."
-        text run at (128,32) width 0: " "
+      RenderBR {BR} at (128,44) size 0x0
+      RenderText {#text} at (0,48) size 128x16
         text run at (0,48) width 128: "Lots of content."
-        text run at (128,48) width 0: " "
-        text run at (0,64) width 0: " "
+      RenderBR {BR} at (128,60) size 0x0
+      RenderBR {BR} at (0,64) size 0x16
+      RenderText {#text} at (0,80) size 128x16
         text run at (0,80) width 128: "Lots of content."
-        text run at (128,80) width 0: " "
+      RenderBR {BR} at (128,92) size 0x0
+      RenderText {#text} at (0,96) size 128x16
         text run at (0,96) width 128: "Lots of content."
-        text run at (128,96) width 0: " "
-        text run at (0,112) width 0: " "
+      RenderBR {BR} at (128,108) size 0x0
+      RenderBR {BR} at (0,112) size 0x16
+      RenderText {#text} at (0,128) size 128x16
         text run at (0,128) width 128: "Lots of content."
-        text run at (128,128) width 0: " "
+      RenderBR {BR} at (128,140) size 0x0
+      RenderText {#text} at (0,144) size 128x16
         text run at (0,144) width 128: "Lots of content."
-        text run at (128,144) width 0: " "
-        text run at (0,160) width 0: " "
+      RenderBR {BR} at (128,156) size 0x0
+      RenderBR {BR} at (0,160) size 0x16
+      RenderText {#text} at (0,176) size 128x16
         text run at (0,176) width 128: "Lots of content."
-        text run at (128,176) width 0: " "
+      RenderBR {BR} at (128,188) size 0x0
+      RenderText {#text} at (0,192) size 128x16
         text run at (0,192) width 128: "Lots of content."
-        text run at (128,192) width 0: " "
-        text run at (0,208) width 0: " "
+      RenderBR {BR} at (128,204) size 0x0
+      RenderBR {BR} at (0,208) size 0x16
+      RenderText {#text} at (0,224) size 128x16
         text run at (0,224) width 128: "Lots of content."
-        text run at (128,224) width 0: " "
+      RenderBR {BR} at (128,236) size 0x0
+      RenderText {#text} at (0,240) size 128x16
         text run at (0,240) width 128: "Lots of content."
-        text run at (128,240) width 0: " "
-        text run at (0,256) width 0: " "
+      RenderBR {BR} at (128,252) size 0x0
+      RenderBR {BR} at (0,256) size 0x16
+      RenderText {#text} at (0,272) size 128x16
         text run at (0,272) width 128: "Lots of content."
-        text run at (128,272) width 0: " "
+      RenderBR {BR} at (128,284) size 0x0
+      RenderText {#text} at (0,288) size 128x16
         text run at (0,288) width 128: "Lots of content."
-        text run at (128,288) width 0: " "
-        text run at (0,304) width 0: " "
+      RenderBR {BR} at (128,300) size 0x0
+      RenderBR {BR} at (0,304) size 0x16
+      RenderText {#text} at (0,320) size 128x16
         text run at (0,320) width 128: "Lots of content."
-        text run at (128,320) width 0: " "
+      RenderBR {BR} at (128,332) size 0x0
+      RenderText {#text} at (0,336) size 128x16
         text run at (0,336) width 128: "Lots of content."
-        text run at (128,336) width 0: " "
-        text run at (0,352) width 0: " "
+      RenderBR {BR} at (128,348) size 0x0
+      RenderBR {BR} at (0,352) size 0x16
       RenderBR {BR} at (0,368) size 0x16