[SVG] DisplayList-based patterns.

LayoutTests/svg/custom/pattern-in-defs.svg

Index: LayoutTests/svg/custom/pattern-in-defs.svg
diff --git a/LayoutTests/svg/custom/pattern-in-defs.svg b/LayoutTests/svg/custom/pattern-in-defs.svg
index 02eddea085eb1605338580f43a0e515ec4f67078..ab3c723bb0276355e424bcef37c3cc0f8dfd20bc 100644
--- a/LayoutTests/svg/custom/pattern-in-defs.svg
+++ b/LayoutTests/svg/custom/pattern-in-defs.svg
@@ -1,6 +1,6 @@
 <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
   <defs>
-    <pattern id="green" x="0" y="0" width="100" height="100">
+    <pattern id="green" x="0" y="0" width="100" height="100" patternUnits="userSpaceOnUse">

[Erik Dahlström (inactive), 2014/08/08 08:01:02]

I'm curious, why was this change needed?

[f(malita), 2014/08/08 15:30:35]

Before I've added tile clamping in Skia, the default OBB units were causing an
attempt to allocate some humongous tile (10000x10000) which was failing => pixel
diff.

With clamping in place everything works as before, but since the intent of the
test is clearly to use userSpaceOnUse units I figured we might as well take the
opportunity to fix it.

       <rect x="0" y="0" width="100" height="100" fill="green"/>
     </pattern>
   </defs>