adoptNode wasn't clearing the accessibility cache.

Source/core/dom/TreeScopeAdopter.cpp

Index: Source/core/dom/TreeScopeAdopter.cpp
diff --git a/Source/core/dom/TreeScopeAdopter.cpp b/Source/core/dom/TreeScopeAdopter.cpp
index 471396f739e2c89ce7db8209076a1dd3b31832da..60a3a4727ecf656df81078cd5ffccb34cf9d96f0 100644
--- a/Source/core/dom/TreeScopeAdopter.cpp
+++ b/Source/core/dom/TreeScopeAdopter.cpp
@@ -25,6 +25,7 @@
 #include "config.h"
 #include "core/dom/TreeScopeAdopter.h"
 
+#include "core/accessibility/AXObjectCache.h"
 #include "core/dom/Attr.h"
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeTraversal.h"
@@ -48,15 +49,18 @@ void TreeScopeAdopter::moveTreeToNewScope(Node& root) const
     Document& oldDocument = oldScope().document();
     Document& newDocument = newScope().document();
     bool willMoveToNewDocument = oldDocument != newDocument;
+    AXObjectCache* axObjectCache = oldDocument.existingAXObjectCache();
     if (willMoveToNewDocument)
         oldDocument.incDOMTreeVersion();
 
     for (Node* node = &root; node; node = NodeTraversal::next(*node, &root)) {
         updateTreeScope(*node);
 
-        if (willMoveToNewDocument)
+        if (willMoveToNewDocument) {
+            if (axObjectCache)
+                axObjectCache->remove(node);
             moveNodeToNewDocument(*node, oldDocument, newDocument);
-        else if (node->hasRareData()) {
+        } else if (node->hasRareData()) {
             NodeRareData* rareData = node->rareData();
             if (rareData->nodeLists())
                 rareData->nodeLists()->adoptTreeScope();