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

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)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 525 matching lines @@
 
         distributeExtraLogicalHeight(floorToInt(computedLogicalHeight - totalSectionLogicalHeight));
 
         bool isPaginated = view()->layoutState()->isPaginated();
         LayoutTableSection* topSection = this->topSection();
         LayoutUnit logicalOffset = topSection ? topSection->logicalTop() : LayoutUnit();
         for (LayoutTableSection* section = topSection; section; section = sectionBelow(section)) {
             section->setLogicalTop(logicalOffset);
             section->layoutRows();
             logicalOffset += section->logicalHeight();
-            if (isPaginated && m_head && m_head == section && section->logicalHeight() < section->pageLogicalHeightForOffset(logicalOffset)) {
+            // If the section is a repeating header group that allows at least one row of content then store the
+            // offset for other sections to offset their rows against.
+            if (isPaginated && m_head && m_head == section && section->logicalHeight() < section->pageLogicalHeightForOffset(logicalOffset)
+                && section->getPaginationBreakability() != LayoutBox::AllowAnyBreaks) {
                 LayoutUnit offsetForTableHeaders = state.heightOffsetForTableHeaders();
-                offsetForTableHeaders += section->logicalHeight();
+                // Don't include any strut in the header group - we only want the height from its content.
+                offsetForTableHeaders += section->logicalHeight() - section->paginationStrutForRow(section->firstRow(), section->logicalTop());

[mstensho (USE GERRIT), 2016/08/10 09:42:48]

section->firstRow() may be nullptr.

                 state.setHeightOffsetForTableHeaders(offsetForTableHeaders);
             }
         }
 
         if (!topSection && computedLogicalHeight > totalSectionLogicalHeight && !document().inQuirksMode()) {
             // Completely empty tables (with no sections or anything) should at least honor specified height
             // in strict mode.
             setLogicalHeight(logicalHeight() + computedLogicalHeight);
         }
 
@@ skipping 948 matching lines @@
 
 LayoutUnit LayoutTable::paddingRight() const
 {
     if (collapseBorders())
         return LayoutUnit();
 
     return LayoutBlock::paddingRight();
 }
 
 } // namespace blink