Oilpan: have xml/ objects on the heap by default.

Source/core/xml/NativeXPathNSResolver.h

Index: Source/core/xml/NativeXPathNSResolver.h
diff --git a/Source/core/xml/NativeXPathNSResolver.h b/Source/core/xml/NativeXPathNSResolver.h
index 002a3f378acc210095cfa39508da3ad1be56ec6d..6a072a773d6d66085e5ea099115fccb64ee477df 100644
--- a/Source/core/xml/NativeXPathNSResolver.h
+++ b/Source/core/xml/NativeXPathNSResolver.h
@@ -35,9 +35,9 @@ class Node;
 
 class NativeXPathNSResolver final : public XPathNSResolver {
 public:
-    static PassRefPtrWillBeRawPtr<NativeXPathNSResolver> create(PassRefPtrWillBeRawPtr<Node> node)
+    static NativeXPathNSResolver* create(PassRefPtrWillBeRawPtr<Node> node)
     {
-        return adoptRefWillBeNoop(new NativeXPathNSResolver(node));
+        return new NativeXPathNSResolver(node);
     }
 
     virtual AtomicString lookupNamespaceURI(const String& prefix) override;