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

Source/core/rendering/RenderMultiColumnFlowThread.h

Index: Source/core/rendering/RenderMultiColumnFlowThread.h
diff --git a/Source/core/rendering/RenderMultiColumnFlowThread.h b/Source/core/rendering/RenderMultiColumnFlowThread.h
index cf36649f763f36e0c7d69aa5a16c24a7f3ffbd76..a0347f529021dffa437e9748576b3b5cbf2b13d6 100644
--- a/Source/core/rendering/RenderMultiColumnFlowThread.h
+++ b/Source/core/rendering/RenderMultiColumnFlowThread.h
@@ -149,11 +149,11 @@ private:
     virtual void addRegionToThread(RenderMultiColumnSet*) OVERRIDE;
     virtual void willBeRemovedFromTree() OVERRIDE;
     virtual bool hasColumnSpanner(const RenderObject*) const OVERRIDE;
-    virtual LayoutUnit spannerLogicalTopAdjustment(RenderBox* renderer, LayoutUnit logicalTop) const OVERRIDE;
-    virtual void enterColumnSpanner(RenderBox*, LayoutUnit& logicalTop) OVERRIDE;
+    virtual LayoutUnit enterColumnSpanner(RenderBox*, LayoutUnit logicalTop) OVERRIDE;
     virtual void leaveColumnSpanner(RenderBox*, LayoutUnit logicalBottom) OVERRIDE;
     virtual void flowThreadDescendantInserted(RenderObject*) OVERRIDE;
     virtual void flowThreadDescendantWillBeRemoved(RenderObject*) OVERRIDE;
+    virtual void flowThreadDescendantStyleDidChange(RenderObject*) OVERRIDE;
     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;
     virtual void updateLogicalWidth() OVERRIDE;
     virtual void setPageBreak(LayoutUnit offset, LayoutUnit spaceShortage) OVERRIDE;