MOZ_COUNT_DTOR(PresShell);
PresShell::~PresShell(){  MOZ_COUNT_DTOR(PresShell);  mRefCnt = 99;/* XXX hack! get around re-entrancy bugs */  mIsDestroying = PR_TRUE;  // Clobber weak leaks in case of re-entrancy during tear down  mHistoryState = nsnull;  NS_IF_RELEASE(mCurrentEventContent);  if (mViewManager) {    // Disable paints during tear down of the frame tree    mViewManager->DisableRefresh();    mViewManager = nsnull;  }  // Destroy the frame manager before destroying the frame hierarchy. That way  // we won't waste time removing content->frame mappings for frames being  // destroyed  NS_IF_RELEASE(mFrameManager);  if (mRootFrame) {    mRootFrame->Destroy(*mPresContext);  }  if (mDocument) {    mDocument->DeleteShell(this);  }  mRefCnt = 0;}