Always give RenderParts a RenderLayer.

LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt

Index: LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt
diff --git a/LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt b/LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt
index a6677183c81929fd729c9fbf128526c30ec5dd2b..e2b1c835d5ac67d554197b51df876b92e8476036 100644
--- a/LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt
+++ b/LayoutTests/platform/linux/svg/hixie/intrinsic/003-expected.txt
@@ -5,11 +5,12 @@ layer at (0,0) size 800x268
     RenderBody {BODY} at (8,16) size 784x236
       RenderBlock {DIV} at (0,0) size 100x200
         RenderBlock {P} at (0,0) size 100x200
-          RenderEmbeddedObject {OBJECT} at (0,0) size 200x200
-            layer at (0,0) size 100x200
-              RenderView at (0,0) size 100x200
-            layer at (0,0) size 100x200
-              RenderSVGRoot {svg} at (0,0) size 0x0
       RenderBlock {P} at (0,216) size 784x20
         RenderText {#text} at (0,0) size 403x19
           text run at (0,0) width 403: "There should be a complete unbroken yin-yang symbol (\x{262F}) above."
+layer at (8,16) size 200x200
+  RenderEmbeddedObject {OBJECT} at (0,0) size 200x200
+    layer at (0,0) size 100x200
+      RenderView at (0,0) size 100x200
+    layer at (0,0) size 100x200
+      RenderSVGRoot {svg} at (0,0) size 0x0