Stop handling the case where oldDocument and newDocument are the same in adoptDocument()

Source/core/dom/NodeRareData.h

Index: Source/core/dom/NodeRareData.h
diff --git a/Source/core/dom/NodeRareData.h b/Source/core/dom/NodeRareData.h
index b1474b90d435f31238f6ea728ea6715cdaa3cfeb..65f903c78e340d63339910aa936533b3acded7ce 100644
--- a/Source/core/dom/NodeRareData.h
+++ b/Source/core/dom/NodeRareData.h
@@ -173,23 +173,22 @@ public:
 
     void adoptDocument(Document& oldDocument, Document& newDocument)
     {
+        ASSERT(oldDocument != newDocument);
         invalidateCaches();
 
-        if (oldDocument != newDocument) {
-            NodeListAtomicNameCacheMap::const_iterator atomicNameCacheEnd = m_atomicNameCaches.end();
-            for (NodeListAtomicNameCacheMap::const_iterator it = m_atomicNameCaches.begin(); it != atomicNameCacheEnd; ++it) {
-                LiveNodeListBase* list = it->value;
-                oldDocument.unregisterNodeList(list);
-                newDocument.registerNodeList(list);
-            }
-
-            TagCollectionCacheNS::const_iterator tagEnd = m_tagCollectionCacheNS.end();
-            for (TagCollectionCacheNS::const_iterator it = m_tagCollectionCacheNS.begin(); it != tagEnd; ++it) {
-                LiveNodeListBase* list = it->value;
-                ASSERT(!list->isRootedAtDocument());
-                oldDocument.unregisterNodeList(list);
-                newDocument.registerNodeList(list);
-            }
+        NodeListAtomicNameCacheMap::const_iterator atomicNameCacheEnd = m_atomicNameCaches.end();
+        for (NodeListAtomicNameCacheMap::const_iterator it = m_atomicNameCaches.begin(); it != atomicNameCacheEnd; ++it) {
+            LiveNodeListBase* list = it->value;
+            oldDocument.unregisterNodeList(list);
+            newDocument.registerNodeList(list);
+        }
+
+        TagCollectionCacheNS::const_iterator tagEnd = m_tagCollectionCacheNS.end();
+        for (TagCollectionCacheNS::const_iterator it = m_tagCollectionCacheNS.begin(); it != tagEnd; ++it) {
+            LiveNodeListBase* list = it->value;
+            ASSERT(!list->isRootedAtDocument());
+            oldDocument.unregisterNodeList(list);
+            newDocument.registerNodeList(list);
         }
     }