Need a deep layout pass when becoming (un)fragmented.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 81 matching lines @@
     : LayoutBox(node),
       m_hasMarginBeforeQuirk(false),
       m_hasMarginAfterQuirk(false),
       m_beingDestroyed(false),
       m_hasMarkupTruncation(false),
       m_widthAvailableToChildrenChanged(false),
       m_heightAvailableToChildrenChanged(false),
       m_isSelfCollapsing(false),
       m_descendantsWithFloatsMarkedForLayout(false),
       m_hasPositionedObjects(false),
-      m_hasPercentHeightDescendants(false) {
+      m_hasPercentHeightDescendants(false),
+      m_paginationStateChanged(false) {
   // LayoutBlockFlow calls setChildrenInline(true).
   // By default, subclasses do not have inline children.
 }
 
 void LayoutBlock::removeFromGlobalMaps() {
   if (hasPositionedObjects()) {
     std::unique_ptr<TrackedLayoutBoxListHashSet> descendants =
         gPositionedDescendantsMap->take(this);
     ASSERT(!descendants->isEmpty());
     for (LayoutBox* descendant : *descendants) {
@@ skipping 2099 matching lines @@
   }
 
   return availableHeight;
 }
 
 bool LayoutBlock::hasDefiniteLogicalHeight() const {
   return availableLogicalHeightForPercentageComputation() != LayoutUnit(-1);
 }
 
 }  // namespace blink