mStack[0].mFlags = APPENDED;
SinkContext::Begin(nsHTMLTag aNodeType,                   nsGenericHTMLElement* aRoot,                   PRUint32 aNumFlushed,                   PRInt32 aInsertionPoint){  if (mStackSize < 1) {    nsresult rv = GrowStack();    if (NS_FAILED(rv)) {      return rv;    }  }  mStack[0].mType = aNodeType;  mStack[0].mContent = aRoot;  mStack[0].mFlags = APPENDED;  mStack[0].mNumFlushed = aNumFlushed;  mStack[0].mInsertionPoint = aInsertionPoint;  NS_ADDREF(aRoot);  mStackPos = 1;  mTextLength = 0;  return NS_OK;}