*** DO NOT LAND *** Measure the size and complexity of the old multicol implementation.

Source/core/rendering/RenderBlockFlow.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003-2013 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ skipping 238 matching lines @@
         return adjustLogicalRightOffsetForLine(logicalRightFloatOffsetForLine(logicalTop, fixedOffset, logicalHeight), applyTextIndent);
     }
     LayoutUnit logicalLeftOffsetForLine(LayoutUnit logicalTop, LayoutUnit fixedOffset, bool applyTextIndent, LayoutUnit logicalHeight = 0) const
     {
         return adjustLogicalLeftOffsetForLine(logicalLeftFloatOffsetForLine(logicalTop, fixedOffset, logicalHeight), applyTextIndent);
     }
 
     virtual void insertedIntoTree() OVERRIDE;
     virtual void willBeDestroyed() OVERRIDE;
 private:
-    void layoutBlockFlow(bool relayoutChildren, LayoutUnit pageLogicalHeight = 0);
+    void layoutBlockFlow(bool relayoutChildren);
     void layoutBlockChildren(bool relayoutChildren, LayoutUnit& maxFloatLogicalBottom, SubtreeLayoutScope&, LayoutUnit beforeEdge, LayoutUnit afterEdge);
 
     void layoutBlockChild(RenderBox* child, MarginInfo&, LayoutUnit& previousFloatLogicalBottom, LayoutUnit& maxFloatLogicalBottom);
     void adjustPositionedBlock(RenderBox* child, const MarginInfo&);
     void adjustFloatingBlock(const MarginInfo&);
 
     LayoutPoint flipFloatForWritingModeForChild(const FloatingObject*, const LayoutPoint&) const;
 
     LayoutUnit xPositionForFloatIncludingMargin(const FloatingObject* child) const
     {
@@ skipping 16 matching lines @@
     FloatingObject* insertFloatingObject(RenderBox*);
     void removeFloatingObject(RenderBox*);
     void removeFloatingObjectsBelow(FloatingObject*, int logicalOffset);
 
     // Called from lineWidth, to position the floats added in the last line.
     // Returns true if and only if it has positioned any floats.
     bool positionNewFloats();
 
     LayoutUnit getClearDelta(RenderBox* child, LayoutUnit yPos);
 
-    bool hasOverhangingFloats() { return parent() && !hasColumns() && containsFloats() && lowestFloatLogicalBottom() > logicalHeight(); }
+    bool hasOverhangingFloats() { return parent() && containsFloats() && lowestFloatLogicalBottom() > logicalHeight(); }
     bool hasOverhangingFloat(RenderBox*);
     void addIntrudingFloats(RenderBlockFlow* prev, LayoutUnit xoffset, LayoutUnit yoffset);
     LayoutUnit addOverhangingFloats(RenderBlockFlow* child, bool makeChildPaintOtherFloats);
 
     LayoutUnit lowestFloatLogicalBottom(FloatingObject::Type = FloatingObject::FloatLeftRight) const;
     LayoutUnit nextFloatLogicalBottomBelow(LayoutUnit, ShapeOutsideFloatOffsetMode = ShapeOutsideFloatMarginBoxOffset) const;
 
     virtual bool hitTestFloats(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset) OVERRIDE FINAL;
 
     virtual void repaintOverhangingFloats(bool paintAllDescendants) OVERRIDE FINAL;
     virtual void repaintOverflow() OVERRIDE FINAL;
     virtual void paintFloats(PaintInfo&, const LayoutPoint&, bool preservePhase = false) OVERRIDE FINAL;
     virtual void clipOutFloatingObjects(RenderBlock*, const PaintInfo*, const LayoutPoint&, const LayoutSize&) OVERRIDE;
     void clearFloats(EClear);
 
     LayoutUnit logicalRightFloatOffsetForLine(LayoutUnit logicalTop, LayoutUnit fixedOffset, LayoutUnit logicalHeight) const;
     LayoutUnit logicalLeftFloatOffsetForLine(LayoutUnit logicalTop, LayoutUnit fixedOffset, LayoutUnit logicalHeight) const;
 
     LayoutUnit logicalRightOffsetForPositioningFloat(LayoutUnit logicalTop, LayoutUnit fixedOffset, bool applyTextIndent, LayoutUnit* heightRemaining) const;
     LayoutUnit logicalLeftOffsetForPositioningFloat(LayoutUnit logicalTop, LayoutUnit fixedOffset, bool applyTextIndent, LayoutUnit* heightRemaining) const;
 
     LayoutUnit adjustLogicalRightOffsetForLine(LayoutUnit offsetFromFloats, bool applyTextIndent) const;
     LayoutUnit adjustLogicalLeftOffsetForLine(LayoutUnit offsetFromFloats, bool applyTextIndent) const;
 
     virtual void adjustForBorderFit(LayoutUnit x, LayoutUnit& left, LayoutUnit& right) const OVERRIDE; // Helper function for borderFitAdjust
 
     virtual RootInlineBox* createRootInlineBox(); // Subclassed by SVG
 
     void updateLogicalWidthForAlignment(const ETextAlign&, const RootInlineBox*, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, int expansionOpportunityCount);
-    virtual bool relayoutForPagination(bool hasSpecifiedPageLogicalHeight, LayoutUnit pageLogicalHeight, LayoutStateMaintainer&);
+    virtual bool relayoutForPagination(bool hasSpecifiedPageLogicalHeight, LayoutUnit pageLogicalHeight, LayoutStateMaintainer&) { return false; }
 public:
     struct FloatWithRect {
         FloatWithRect(RenderBox* f)
             : object(f)
             , rect(LayoutRect(f->x() - f->marginLeft(), f->y() - f->marginTop(), f->width() + f->marginWidth(), f->height() + f->marginHeight()))
             , everHadLayout(f->everHadLayout())
         {
         }
 
         RenderBox* object;
@@ skipping 183 matching lines @@
 
 // END METHODS DEFINED IN RenderBlockLineLayout
 
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlockFlow, isRenderBlockFlow());
 
 } // namespace WebCore
 
 #endif // RenderBlockFlow_h