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

third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp

 /*
  * 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 20 matching lines @@
 #include "core/layout/MultiColumnFragmentainerGroup.h"
 #include "core/paint/MultiColumnSetPainter.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 LayoutMultiColumnSet::LayoutMultiColumnSet(LayoutFlowThread* flowThread)
     : LayoutBlockFlow(nullptr)
     , m_fragmentainerGroups(*this)
     , m_flowThread(flowThread)
+    , m_initialHeightCalculated(false)
 {
 }
 
 LayoutMultiColumnSet* LayoutMultiColumnSet::createAnonymous(LayoutFlowThread& flowThread, const ComputedStyle& parentStyle)
 {
     Document& document = flowThread.document();
     LayoutMultiColumnSet* layoutObject = new LayoutMultiColumnSet(&flowThread);
     layoutObject->setDocumentForAnonymous(&document);
     layoutObject->setStyle(ComputedStyle::createAnonymousStyleWithDisplay(parentStyle, BLOCK));
     return layoutObject;
@@ skipping 186 matching lines @@
 {
     const MultiColumnFragmentainerGroup& row = fragmentainerGroupAtVisualPoint(visualPoint);
     return row.visualPointToFlowThreadPoint(visualPoint - row.offsetFromColumnSet());
 }
 
 LayoutUnit LayoutMultiColumnSet::pageLogicalTopForOffset(LayoutUnit offset) const
 {
     return fragmentainerGroupAtFlowThreadOffset(offset).columnLogicalTopForOffset(offset);
 }
 
-bool LayoutMultiColumnSet::recalculateColumnHeight(BalancedColumnHeightCalculation calculationMode)
+bool LayoutMultiColumnSet::recalculateColumnHeight()
 {
-    if (calculationMode == GuessFromFlowThreadPortion)
-        m_tallestUnbreakableLogicalHeight = LayoutUnit();
+    if (m_oldLogicalTop != logicalTop() && multiColumnFlowThread()->enclosingFlowThread()) {
+        // Preceding spanners or column sets have been moved or resized. This means that the
+        // fragmentainer groups that we have inserted need to be re-inserted. Restart column
+        // balancing.
+        resetColumnHeight();
+        return true;
+    }
+
     bool changed = false;
     for (auto& group : m_fragmentainerGroups)
-        changed = group.recalculateColumnHeight(calculationMode) || changed;
+        changed = group.recalculateColumnHeight() || changed;
+    m_initialHeightCalculated = true;
     return changed;
 }
 
 void LayoutMultiColumnSet::resetColumnHeight()
 {
     m_fragmentainerGroups.deleteExtraGroups();
     m_fragmentainerGroups.first().resetColumnHeight();
+    m_tallestUnbreakableLogicalHeight = LayoutUnit();
+    m_initialHeightCalculated = false;
 }
 
 void LayoutMultiColumnSet::beginFlow(LayoutUnit offsetInFlowThread)
 {
     // At this point layout is exactly at the beginning of this set. Store block offset from flow
     // thread start.
     m_fragmentainerGroups.first().setLogicalTopInFlowThread(offsetInFlowThread);
 }
 
 void LayoutMultiColumnSet::endFlow(LayoutUnit offsetInFlowThread)
@@ skipping 109 matching lines @@
 
 LayoutRect LayoutMultiColumnSet::flowThreadPortionRect() const
 {
     LayoutRect portionRect(LayoutUnit(), logicalTopInFlowThread(), pageLogicalWidth(), logicalHeightInFlowThread());
     if (!isHorizontalWritingMode())
         return portionRect.transposedRect();
     return portionRect;
 }
 
 }