mRCCreatedDuringLoad = 0; mDummyLayoutRequest = nsnull;
PresShell::PresShell():mStackArena(nsnull),                       mFirstDOMEventRequest(nsnull),                       mLastDOMEventRequest(nsnull),                       mFirstAttributeRequest(nsnull),                       mLastAttributeRequest(nsnull),                       mFirstCallbackEventRequest(nsnull),                       mLastCallbackEventRequest(nsnull){  NS_INIT_REFCNT();  mIsDestroying = PR_FALSE;  mCaretEnabled = PR_FALSE;  mDisplayNonTextSelection = PR_FALSE;  mCurrentEventContent = nsnull;  mCurrentEventFrame = nsnull;  EnableScrolling();#ifdef NS_DEBUG  mCurrentTargetView = nsnull;#endif  mPendingReflowEvent = PR_FALSE;      mBatchReflows = PR_FALSE;  mDocumentLoading = PR_FALSE;  mSubShellMap = nsnull;#ifdef MOZ_REFLOW_PERF  mReflowCountMgr = new ReflowCountMgr();#endif}