*** DO NOT LAND *** Implement column-span:all without reparenting renderers. Work in progress.

Source/core/rendering/RenderMultiColumnSpannerSet.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef RenderMultiColumnSpannerSet_h
 #define RenderMultiColumnSpannerSet_h
 
 #include "core/rendering/RenderMultiColumnSet.h"
 
 namespace blink {
 
 class RenderMultiColumnSpannerSet FINAL : public RenderMultiColumnSet {
 public:
     virtual bool isRenderMultiColumnSpannerSet() const OVERRIDE { return true; }
 
     static RenderMultiColumnSpannerSet* createAnonymous(RenderMultiColumnFlowThread*, RenderStyle* parentStyle, RenderBox*);
 
     RenderBox* renderer() const { return m_renderer; }
+    void updateMarginProperties(RenderStyle* newStyle, const RenderObject* spannerBlock) const;
+
     virtual bool recalculateColumnHeight(BalancedHeightCalculation) OVERRIDE;
 
 protected:
     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;
     virtual LayoutUnit pageLogicalHeight() const OVERRIDE;
     virtual const char* renderName() const OVERRIDE;
 
 private:
     RenderMultiColumnSpannerSet(RenderMultiColumnFlowThread*, RenderBox*);
 
     RenderBox* m_renderer; // The column span renderer.
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMultiColumnSpannerSet, isRenderMultiColumnSpannerSet());
 
 } // namespace blink
 
 #endif