return rv; }
  PRBool GetCachedBoolPref(PRUint32 aPrefType) const  {    // If called with a constant parameter, the compiler should optimize    // this switch statement away.    switch (aPrefType) {    case kPresContext_UseDocumentFonts:      return mUseDocumentFonts;    case kPresContext_UseDocumentColors:      return mUseDocumentColors;    case kPresContext_UnderlineLinks:      return mUnderlineLinks;    default:      NS_ERROR("Invalid arg passed to GetCachedBoolPref");    }    return PR_FALSE;  }