mAccessible = do_QueryInterface(frame);
frame->GetAccessible(getter_AddRefs(mAccessible));
PRBool nsDOMTreeWalker::GetAccessible(){  mAccessible = nsnull;  nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));  if (!content)    return PR_FALSE;  nsCOMPtr<nsIDOMHTMLAreaElement> areaContent(do_QueryInterface(mDOMNode));  if (areaContent)   // Area elements are implemented in nsHTMLImageAccessible as children of the image    return PR_FALSE; // Return, otherwise the image frame looks like an accessible object in the wrong place  nsIFrame* frame = GetPrimaryFrame();  if (!frame)    return PR_FALSE;  mAccessible = do_QueryInterface(frame);  if (!mAccessible)    mAccessible = do_QueryInterface(mDOMNode);  if (!mAccessible) {    // is it a link?    nsCOMPtr<nsILink> link(do_QueryInterface(mDOMNode));    if (link) {       nsCOMPtr<nsIPresShell> shell(do_QueryReferent(mPresShell));       mAccessible = new nsHTMLLinkAccessible(shell, mDOMNode);    }  }  if (mAccessible)    return PR_TRUE;  else    return PR_FALSE;}