Avoid pathological layout on nested percent height tables

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

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
@@ skipping 433 matching lines @@
 }
 
 void LayoutTable::layoutSection(LayoutTableSection& section,
                                 SubtreeLayoutScope& layouter,
                                 LayoutUnit logicalLeft) {
   section.setLogicalLocation(LayoutPoint(logicalLeft, logicalHeight()));
   if (m_columnLogicalWidthChanged)
     layouter.setChildNeedsLayout(&section);
   if (!section.needsLayout())
     markChildForPaginationRelayoutIfNeeded(section, layouter);
+  bool neededLayout = section.needsLayout();

[mstensho (USE GERRIT), 2017/02/06 21:11:07]

Might as well do:

if (section.needsLayout()) {
  section.layout();
  section.setLogicalHeight(LayoutUnit(section.calcRowLogicalHeight()));
}

[rhogan, 2017/02/06 21:21:08]

section.layout() is private, should I just make it public?

[mstensho (USE GERRIT), 2017/02/06 21:25:27]

Oh. Yes. This is exactly why it's problematic to override a public method as
private. :)

   section.layoutIfNeeded();
-  int sectionLogicalHeight = section.calcRowLogicalHeight();
-  section.setLogicalHeight(LayoutUnit(sectionLogicalHeight));
+  if (neededLayout)
+    section.setLogicalHeight(LayoutUnit(section.calcRowLogicalHeight()));
   if (view()->layoutState()->isPaginated())
     updateFragmentationInfoForChild(section);
-  setLogicalHeight(logicalHeight() + sectionLogicalHeight);
+  setLogicalHeight(logicalHeight() + section.logicalHeight());
 }
 
 LayoutUnit LayoutTable::logicalHeightFromStyle() const {
   LayoutUnit computedLogicalHeight;
   Length logicalHeightLength = style()->logicalHeight();
   if (logicalHeightLength.isIntrinsic() ||
       (logicalHeightLength.isSpecified() && logicalHeightLength.isPositive())) {
     computedLogicalHeight =
         convertStyleLogicalHeightToComputedHeight(logicalHeightLength);
   }
@@ skipping 1218 matching lines @@
 }
 
 LayoutUnit LayoutTable::paddingRight() const {
   if (collapseBorders())
     return LayoutUnit();
 
   return LayoutBlock::paddingRight();
 }
 
 }  // namespace blink