Be more restrictive about forcing relayout of children for pagination.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 63 matching lines @@
   LayoutMultiColumnSpannerPlaceholder* m_spannerPlaceholder;
 
   LayoutUnit m_overrideLogicalContentWidth;
   LayoutUnit m_overrideLogicalContentHeight;
 
   bool m_hasOverrideContainingBlockContentLogicalWidth;
   bool m_hasOverrideContainingBlockContentLogicalHeight;
   LayoutUnit m_overrideContainingBlockContentLogicalWidth;
   LayoutUnit m_overrideContainingBlockContentLogicalHeight;
 
-  LayoutUnit m_pageLogicalOffset;
+  LayoutUnit m_offsetToNextPage;
+
   LayoutUnit m_paginationStrut;
 
   LayoutBlock* m_percentHeightContainer;
   // For snap area, the owning snap container.
   LayoutBox* m_snapContainer;
   // For snap container, the descendant snap areas that contribute snap
   // points.
   std::unique_ptr<SnapAreaSet> m_snapAreas;
 
   SnapAreaSet& ensureSnapAreas() {
@@ skipping 148 matching lines @@
   }
   LayoutUnit logicalBottom() const { return logicalTop() + logicalHeight(); }
   LayoutUnit logicalWidth() const {
     return style()->isHorizontalWritingMode() ? m_frameRect.width()
                                               : m_frameRect.height();
   }
   LayoutUnit logicalHeight() const {
     return style()->isHorizontalWritingMode() ? m_frameRect.height()
                                               : m_frameRect.width();
   }
+  LayoutUnit logicalHeightIncludingOverflow() const;
 
   LayoutUnit constrainLogicalWidthByMinMax(LayoutUnit,
                                            LayoutUnit,
                                            LayoutBlock*) const;
   LayoutUnit constrainLogicalHeightByMinMax(
       LayoutUnit logicalHeight,
       LayoutUnit intrinsicContentHeight) const;
   LayoutUnit constrainContentBoxLogicalHeightByMinMax(
       LayoutUnit logicalHeight,
       LayoutUnit intrinsicContentHeight) const;
@@ skipping 492 matching lines @@
                                   LayoutUnit& marginStart,
                                   LayoutUnit& marginEnd,
                                   Length marginStartLength,
                                   Length marginStartEnd) const;
 
   // Used to resolve margins in the containing block's block-flow direction.
   void computeAndSetBlockDirectionMargins(const LayoutBlock* containingBlock);
 
   LayoutUnit offsetFromLogicalTopOfFirstPage() const;
 
-  // The page logical offset is the object's offset from the top of the page in
-  // the page progression direction (so an x-offset in vertical text and a
-  // y-offset for horizontal text).
-  LayoutUnit pageLogicalOffset() const {
-    return m_rareData ? m_rareData->m_pageLogicalOffset : LayoutUnit();
+  // The block offset from the logical top of this object to the end of the
+  // first fragmentainer it lives in. If it only lives in one fragmentainer, 0
+  // is returned.
+  LayoutUnit offsetToNextPage() const {
+    return m_rareData ? m_rareData->m_offsetToNextPage : LayoutUnit();
   }
-  void setPageLogicalOffset(LayoutUnit);
+  void setOffsetToNextPage(LayoutUnit);
 
   // Specify which page or column to associate with an offset, if said offset is
   // exactly at a page or column boundary.
   enum PageBoundaryRule { AssociateWithFormerPage, AssociateWithLatterPage };
   LayoutUnit pageLogicalHeightForOffset(LayoutUnit) const;
   LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit,
                                                  PageBoundaryRule) const;
+
   bool crossesPageBoundary(LayoutUnit offset, LayoutUnit logicalHeight) const;
 
   // Calculate the strut to insert in order fit content of size
   // |contentLogicalHeight|. |strutToNextPage| is the strut to add to |offset|
   // to merely get to the top of the next page or column. This is what will be
   // returned if the content can actually fit there. Otherwise, return the
   // distance to the next fragmentainer that can fit this piece of content.
   virtual LayoutUnit calculatePaginationStrutToFitContent(
       LayoutUnit offset,
       LayoutUnit strutToNextPage,
@@ skipping 296 matching lines @@
   virtual int inlineBlockBaseline(LineDirectionMode) const {
     return -1;
   }  // Returns -1 if we should skip this box when computing the baseline of an
      // inline-block.
 
   virtual Node* nodeForHitTest() const { return node(); }
 
   bool shrinkToAvoidFloats() const;
   virtual bool avoidsFloats() const;
 
+  void updateFragmentationInfoForChild(LayoutBox& child);
+
   void markChildForPaginationRelayoutIfNeeded(LayoutBox& child,
                                               SubtreeLayoutScope&);
 
   bool isWritingModeRoot() const {
     return !parent() ||
            parent()->style()->getWritingMode() != style()->getWritingMode();
   }
   bool isOrthogonalWritingModeRoot() const {
     return parent() &&
            parent()->isHorizontalWritingMode() != isHorizontalWritingMode();
@@ skipping 510 matching lines @@
 
 inline bool LayoutBox::isForcedFragmentainerBreakValue(EBreak breakValue) {
   return breakValue == BreakColumn || breakValue == BreakLeft ||
          breakValue == BreakPage || breakValue == BreakRecto ||
          breakValue == BreakRight || breakValue == BreakVerso;
 }
 
 }  // namespace blink
 
 #endif  // LayoutBox_h