[New multicol] Eliminate the need for RenderMultiColumnBlock.

Source/core/rendering/RenderMultiColumnFlowThread.h

 /*
  * 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 17 matching lines @@
 #define RenderMultiColumnFlowThread_h
 
 #include "core/rendering/RenderFlowThread.h"
 
 namespace WebCore {
 
 class RenderMultiColumnFlowThread FINAL : public RenderFlowThread {
 public:
     virtual ~RenderMultiColumnFlowThread();
 
-    static RenderMultiColumnFlowThread* createAnonymous(Document*);
+    static RenderMultiColumnFlowThread* createAnonymous(Document&, RenderStyle* parentStyle);
+
+    RenderBlockFlow* multiColumnBlockFlow() const { return toRenderBlockFlow(parent()); }
+    unsigned columnCount() const { return m_columnCount; }
+    LayoutUnit columnWidth() const { return m_columnWidth; }
+    LayoutUnit columnHeightAvailable() const { return m_columnHeightAvailable; }
+    void setColumnHeightAvailable(LayoutUnit available) { m_columnHeightAvailable = available; }
+    bool requiresBalancing() const { return !columnHeightAvailable() || multiColumnBlockFlow()->style()->columnFill() == ColumnFillBalance; }
+
+    void layoutColumns(bool relayoutChildren, SubtreeLayoutScope&);
+    bool computeColumnCountAndWidth();
+    bool recalculateColumnHeights();
 
 private:
     RenderMultiColumnFlowThread();
 
     virtual const char* renderName() const OVERRIDE;
     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;
     virtual void autoGenerateRegionsToBlockOffset(LayoutUnit) OVERRIDE;
     virtual LayoutUnit initialLogicalWidth() const OVERRIDE;
     virtual void setPageBreak(LayoutUnit offset, LayoutUnit spaceShortage) OVERRIDE;
     virtual void updateMinimumPageHeight(LayoutUnit offset, LayoutUnit minHeight) OVERRIDE;
     virtual bool addForcedRegionBreak(LayoutUnit, RenderObject* breakChild, bool isBefore, LayoutUnit* offsetBreakAdjustment = 0) OVERRIDE;
+
+    unsigned m_columnCount; // The used value of column-count
+    LayoutUnit m_columnWidth; // The used value of column-width
+    LayoutUnit m_columnHeightAvailable; // Total height available to columns, or 0 if auto.
+    bool m_inBalancingPass; // Set when relayouting for column balancing.
+    bool m_needsRebalancing;
 };
 
 } // namespace WebCore
 
 #endif // RenderMultiColumnFlowThread_h