return (mMutationBits & aMutationEventType) != 0;
const nsPIDOMWindow *win = GetCurrentInnerWindow();  if (!win) { win = this; }  return (win->mMutationBits & aMutationEventType) != 0;
  PRBool HasMutationListeners(PRUint32 aMutationEventType)  {    return (mMutationBits & aMutationEventType) != 0;  }