NS_INIT_ISUPPORTS();
StyleSetImpl::StyleSetImpl()  : mFrameConstructor(nsnull),    mQuirkStyleSheet(nsnull),    mRuleTree(nsnull),    mOldRuleTree(nsnull),    mRuleWalker(nsnull),    mRuleMappings(32)#ifdef MOZ_PERF_METRICS    ,mTimerEnabled(PR_FALSE)#endif{  NS_INIT_ISUPPORTS();  if (gInstances++ == 0)  {    static const char kQuirk_href[] = "resource:/res/quirk.css";    NS_NewURI (&gQuirkURI, NS_LITERAL_CSTRING(kQuirk_href));    NS_ASSERTION (gQuirkURI != 0, "Cannot allocate nsStyleSetImpl::gQuirkURI");  }}