NS_ASSERTION((node->mContent != aNode->mContent) || ((node->mContent == nsnull) && (node->mStyle != aNode->mStyle)), "node in map twice");
if (node->mContent == aNode->mContent) {    NS_NOTREACHED("node in map twice"); delete aNode; return NS_OK; }
UndisplayedMap::AppendNodeFor(UndisplayedNode* aNode, nsIContent* aParentContent){  PLHashEntry** entry = GetEntryFor(aParentContent);  if (*entry) {    UndisplayedNode*  node = (UndisplayedNode*)((*entry)->value);    while (node->mNext) {      NS_ASSERTION((node->mContent != aNode->mContent) ||                   ((node->mContent == nsnull) &&                     (node->mStyle != aNode->mStyle)), "node in map twice");      node = node->mNext;    }    node->mNext = aNode;  }  else {    PLHashNumber hashCode = NS_PTR_TO_INT32(aParentContent);    PL_HashTableRawAdd(mTable, entry, hashCode, aParentContent, aNode);    mLastLookup = nsnull; // hashtable may have shifted bucket out from under us  }  return NS_OK;}