Offset repeating theads correctly when two tables adjoin at a page border

third_party/WebKit/Source/core/layout/LayoutTableSection.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, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1107 matching lines @@
 
     ASSERT(!needsLayout());
 
     setLogicalHeight(LayoutUnit(m_rowPos[totalRows]));
 
     computeOverflowFromCells(totalRows, nEffCols);
 }
 
 int LayoutTableSection::paginationStrutForRow(LayoutTableRow* row, LayoutUnit logicalOffset) const
 {
+    DCHECK(row);
     // Even if the row allows us to break-inside, we will want to put a strut on the row if we have a header
     // group that wants to appear at the top of each page.
     bool tableHeaderForcesStrut = table()->header() ? table()->header()->getPaginationBreakability() != AllowAnyBreaks : false;
     if (row->getPaginationBreakability() == AllowAnyBreaks && !tableHeaderForcesStrut)
         return 0;
     LayoutUnit pageLogicalHeight = pageLogicalHeightForOffset(logicalOffset);
     if (!pageLogicalHeight)
         return 0;
     // If the row is too tall for the page don't insert a strut.
     LayoutUnit rowLogicalHeight = row->logicalHeight();
@@ skipping 586 matching lines @@
     // Repeating table headers are painted once per fragmentation page/column. This does not go through the regular fragmentation machinery,
     // so we need special code to expand the invalidation rect to contain all positions of the header in all columns.
     // Note that this is in flow thread coordinates, not visual coordinates. The enclosing LayoutFlowThread will convert to visual coordinates.
     if (table()->header() == this && hasRepeatingHeaderGroup())
         rect.setHeight(table()->logicalHeight());
     return LayoutTableBoxComponent::mapToVisualRectInAncestorSpace(ancestor, rect, flags);
 }
 
 
 } // namespace blink