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

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 4682 matching lines @@
       return true;
   }
   return false;
 }
 
 void LayoutBox::markChildForPaginationRelayoutIfNeeded(
     LayoutBox& child,
     SubtreeLayoutScope& layoutScope) {
   DCHECK(!child.needsLayout());
   LayoutState* layoutState = view()->layoutState();
+  if (layoutState->paginationStateChanged()) {
+    layoutScope.setChildNeedsLayout(&child);
+    return;
+  }
   if (!layoutState->isPaginated())
     return;
 
   if (layoutState->pageLogicalHeightChanged() ||
       (layoutState->pageLogicalHeight() &&
        layoutState->pageLogicalOffset(child, child.logicalTop()) !=
            child.pageLogicalOffset()))
     layoutScope.setChildNeedsLayout(&child);
 }
 
@@ skipping 873 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink