Cleanup: Only need one bit (not two) to express flow thread state.

Source/core/layout/LayoutMultiColumnFlowThread.cpp

 /*
  * Copyright (C) 2012 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 LayoutMultiColumnFlowThread::LayoutMultiColumnFlowThread()
     : m_lastSetWorkedOn(0)
     , m_columnCount(1)
     , m_columnHeightAvailable(0)
     , m_inBalancingPass(false)
     , m_needsColumnHeightsRecalculation(false)
     , m_progressionIsInline(true)
     , m_isBeingEvacuated(false)
 {
-    setFlowThreadState(InsideInFlowThread);
+    setIsInsideFlowThread(true);
 }
 
 LayoutMultiColumnFlowThread::~LayoutMultiColumnFlowThread()
 {
 }
 
 LayoutMultiColumnFlowThread* LayoutMultiColumnFlowThread::createAnonymous(Document& document, const ComputedStyle& parentStyle)
 {
     LayoutMultiColumnFlowThread* layoutObject = new LayoutMultiColumnFlowThread();
     layoutObject->setDocumentForAnonymous(&document);
@@ skipping 676 matching lines @@
 }
 
 bool LayoutMultiColumnFlowThread::isPageLogicalHeightKnown() const
 {
     if (LayoutMultiColumnSet* columnSet = lastMultiColumnSet())
         return columnSet->pageLogicalHeight();
     return false;
 }
 
 }