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

Source/core/xml/XPathFunctions.h

Index: Source/core/xml/XPathFunctions.h
diff --git a/Source/core/xml/XPathFunctions.h b/Source/core/xml/XPathFunctions.h
index 85365e6420364aff1659cb4d3e9205526f8c0d3c..837498a57608982534cce0c14ed5f51843d4a594 100644
--- a/Source/core/xml/XPathFunctions.h
+++ b/Source/core/xml/XPathFunctions.h
@@ -35,7 +35,7 @@ namespace XPath {
 
 class Function : public Expression {
 public:
-    void setArguments(WillBeHeapVector<OwnPtrWillBeMember<Expression>>&);
+    void setArguments(HeapVector<Member<Expression>>&);
     void setName(const String& name) { m_name = name; }
 
 protected:
@@ -49,7 +49,7 @@ private:
 };
 
 Function* createFunction(const String& name);
-Function* createFunction(const String& name, WillBeHeapVector<OwnPtrWillBeMember<Expression>>&);
+Function* createFunction(const String& name, HeapVector<Member<Expression>>&);
 
 } // namespace XPath