column-span:all in nested multicol requires re-insertion of fragmentainer groups.

third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.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 101 matching lines @@
 
     // Find the column that contains the given block offset, and return the translation needed to
     // get from flow thread coordinates to visual coordinates.
     LayoutSize flowThreadTranslationAtOffset(LayoutUnit) const;
 
     LayoutPoint visualPointToFlowThreadPoint(const LayoutPoint& visualPoint) const;
 
     // (Re-)calculate the column height if it's auto. This is first and foremost needed by sets that
     // are to balance the column height, but even when it isn't to be balanced, this is necessary if
     // the multicol container's height is constrained.
-    bool recalculateColumnHeight(BalancedColumnHeightCalculation);
+    bool recalculateColumnHeight();
 
     // Reset previously calculated column height. Will mark for layout if needed.
     void resetColumnHeight();
 
+    void storeOldPosition() { m_oldLogicalTop = logicalTop(); }
+    bool isInitialHeightCalculated() const { return m_initialHeightCalculated; }
+
     // Layout of flow thread content that's to be rendered inside this column set begins. This
     // happens at the beginning of flow thread layout, and when advancing from a previous column set
     // or spanner to this one.
     void beginFlow(LayoutUnit offsetInFlowThread);
 
     // Layout of flow thread content that was to be rendered inside this column set has
     // finished. This happens at end of flow thread layout, and when advancing to the next column
     // set or spanner.
     void endFlow(LayoutUnit offsetInFlowThread);
 
@@ skipping 37 matching lines @@
     MultiColumnFragmentainerGroupList m_fragmentainerGroups;
     LayoutFlowThread* m_flowThread;
 
     // Height of the tallest piece of unbreakable content. This is the minimum column logical height
     // required to avoid fragmentation where it shouldn't occur (inside unbreakable content, between
     // orphans and widows, etc.). We only store this so that outer fragmentation contexts (if any)
     // can query this when calculating their own minimum. Note that we don't store this value in
     // every fragmentainer group (but rather here, in the column set), since we only need the
     // largest one among them.
     LayoutUnit m_tallestUnbreakableLogicalHeight;
+
+    // Logical top in previous layout pass.
+    LayoutUnit m_oldLogicalTop;
+
+    bool m_initialHeightCalculated;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutMultiColumnSet, isLayoutMultiColumnSet());
 
 } // namespace blink
 
 #endif // LayoutMultiColumnSet_h