msxml3: Add a function to initialize xmlDoc->_private data.

dlls/msxml3/domdoc.c

@@ -393,6 +393,12 @@ static xmlDocPtr doparse(domdoc* This, char *ptr, int len)
     return doc;
 }
 
+void xmldoc_init(xmlDocPtr doc, const GUID *clsid)
+{
+    doc->_private = create_priv();
+    priv_from_xmlDocPtr(doc)->properties = create_properties(clsid);
+}
+
 LONG xmldoc_add_ref(xmlDocPtr doc)
 {
     LONG ref = InterlockedIncrement(&priv_from_xmlDocPtr(doc)->refs);

dlls/msxml3/msxml_private.h

@@ -130,6 +130,7 @@ xmlNodePtr xmlNodePtr_from_domnode( IXMLDOMNode *iface, xmlElementType type );
 /* helpers */
 extern xmlChar *xmlChar_from_wchar( LPCWSTR str );
 
+extern void xmldoc_init( xmlDocPtr doc, const GUID *clsid );
 extern LONG xmldoc_add_ref( xmlDocPtr doc );
 extern LONG xmldoc_release( xmlDocPtr doc );
 extern HRESULT xmldoc_add_orphan( xmlDocPtr doc, xmlNodePtr node );