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

Source/core/rendering/RenderFlowThread.h

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 50 matching lines @@
     virtual bool isRenderMultiColumnFlowThread() const { return false; }
     virtual bool isRenderPagedFlowThread() const { return false; }
 
     virtual void layout() OVERRIDE;
 
     // Always create a RenderLayer for the RenderFlowThread so that we
     // can easily avoid drawing the children directly.
     virtual LayerType layerTypeRequired() const OVERRIDE FINAL { return NormalLayer; }
 
     virtual bool hasColumnSpanner(const RenderObject*) const { return false; }
-    virtual LayoutUnit spannerLogicalTopAdjustment(RenderBox* renderer, LayoutUnit logicalTop) const { return LayoutUnit(); }
-    virtual void enterColumnSpanner(RenderBox*, LayoutUnit& logicalTop) { }
+    virtual LayoutUnit enterColumnSpanner(RenderBox*, LayoutUnit logicalTop) { return LayoutUnit(); }
     virtual void leaveColumnSpanner(RenderBox*, LayoutUnit logicalBottom) { }
     virtual void flowThreadDescendantInserted(RenderObject*) { }
     virtual void flowThreadDescendantWillBeRemoved(RenderObject*) { }
+    virtual void flowThreadDescendantStyleDidChange(RenderObject*) { }
 
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) OVERRIDE FINAL;
 
     virtual void addRegionToThread(RenderMultiColumnSet*) = 0;
     virtual void removeRegionFromThread(RenderMultiColumnSet*);
 
     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;
 
     bool hasRegions() const { return m_multiColumnSetList.size(); }
 
@@ skipping 135 matching lines @@
 };
 
 template <> struct ValueToString<RenderMultiColumnSet*> {
     static String string(const RenderMultiColumnSet* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace blink
 
 #endif // RenderFlowThread_h