Document.adoptNode should not throw an exception for DocumentType argument

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 990 matching lines @@
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 PassRefPtrWillBeRawPtr<Node> Document::adoptNode(PassRefPtrWillBeRawPtr<Node> source, ExceptionState& exceptionState)
 {
     EventQueueScope scope;
 
     switch (source->nodeType()) {
     case DOCUMENT_NODE:
-    case DOCUMENT_TYPE_NODE:
         exceptionState.throwDOMException(NotSupportedError, "The node provided is of type '" + source->nodeName() + "', which may not be adopted.");
         return nullptr;
     case ATTRIBUTE_NODE: {
         Attr* attr = toAttr(source.get());
         if (RefPtrWillBeRawPtr<Element> ownerElement = attr->ownerElement())
             ownerElement->removeAttributeNode(attr, exceptionState);
         break;
     }
     default:
         if (source->isShadowRoot()) {
@@ skipping 4795 matching lines @@
     visitor->trace(m_compositorPendingAnimations);
     visitor->trace(m_contextDocument);
     visitor->registerWeakMembers<Document, &Document::clearWeakMembers>(this);
     DocumentSupplementable::trace(visitor);
     TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
     ExecutionContext::trace(visitor);
 }
 
 } // namespace WebCore