[DOM4] Doctypes now always have a node document and can be moved across document boundaries

Source/core/dom/DOMImplementation.cpp

Index: Source/core/dom/DOMImplementation.cpp
diff --git a/Source/core/dom/DOMImplementation.cpp b/Source/core/dom/DOMImplementation.cpp
index 14c51fefa766c6eb8489aa2926b7b4a991575439..3b888bce79dc1d4f970dc35734d4ad6e59945bc6 100644
--- a/Source/core/dom/DOMImplementation.cpp
+++ b/Source/core/dom/DOMImplementation.cpp
@@ -184,7 +184,7 @@ PassRefPtr<DocumentType> DOMImplementation::createDocumentType(const String& qua
     if (!Document::parseQualifiedName(qualifiedName, prefix, localName, es))
         return 0;
 
-    return DocumentType::create(0, qualifiedName, publicId, systemId);
+    return DocumentType::create(m_document, qualifiedName, publicId, systemId);
 }
 
 DOMImplementation* DOMImplementation::getInterface(const String& /*feature*/)
@@ -213,16 +213,6 @@ PassRefPtr<Document> DOMImplementation::createDocument(const String& namespaceUR
             return 0;
     }
 
-    // WrongDocumentError: Raised if doctype has already been used with a different document or was
-    // created from a different implementation.
-    // Hixie's interpretation of the DOM Core spec suggests we should prefer
-    // other exceptions to WrongDocumentError (based on order mentioned in spec),
-    // but this matches the new DOM Core spec (http://www.w3.org/TR/domcore/).
-    if (doctype && doctype->document()) {
-        es.throwDOMException(WrongDocumentError);
-        return 0;
-    }
-
     if (doctype)
         doc->appendChild(doctype);
     if (documentElement)