Node.contains should return true for nodes in Shadow DOM.

Source/core/dom/Node.idl

Index: Source/core/dom/Node.idl
diff --git a/Source/core/dom/Node.idl b/Source/core/dom/Node.idl
index b14d4f74e3c9a304be2258d8afff60c22bb49c46..6f419fa7f8104e41fe5a65f99520c02c60fe6858 100644
--- a/Source/core/dom/Node.idl
+++ b/Source/core/dom/Node.idl
@@ -91,7 +91,7 @@
     unsigned short     compareDocumentPosition([Default=Undefined] optional Node other);
 
     // Introduced in DOM4
-    boolean contains([Default=Undefined] optional Node other);
+    [ImplementedAs=containsIncludingShadowDOM] boolean contains([Default=Undefined] optional Node other);

[esprehn, 2013/07/30 00:29:13]

This is not right, containsIncludingShadowDOM walks up the tree every time,
Node::contains has a bunch of optimizations in it.

 
     // IE extensions
     [PerWorldBindings] readonly attribute Element          parentElement;