Merge 80797

Source/WebCore/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 740 matching lines @@
 
     return false;
 }
 
 void Node::setDocumentRecursively(Document* document)
 {
     // FIXME: To match Gecko, we should do this for nodes that are already in the document as well.
     if (this->document() == document || this->inDocument())
         return;
 
+    // If an element is moved from a document and then eventually back again the collection cache for
+    // that element may contain stale data as changes made to it will have updated the DOMTreeVersion
+    // of the document it was moved to. By increasing the DOMTreeVersion of the donating document here
+    // we ensure that the collection cache will be invalidated as needed when the element is moved back.
+    if (this->document())
+        this->document()->incDOMTreeVersion();
+
     for (Node* node = this; node; node = node->traverseNextNode(this)) {
         node->setDocument(document);
         if (!node->isElementNode())
             continue;
         if (Node* shadow = toElement(node)->shadowRoot())
             shadow->setDocumentRecursively(document);
     }
 }
 
 inline void Node::setStyleChange(StyleChangeType changeType)
@@ skipping 2276 matching lines @@
 
 #ifndef NDEBUG
 
 void showTree(const WebCore::Node* node)
 {
     if (node)
         node->showTreeForThis();
 }
 
 #endif