Move below headers even when row doesn't require a strut

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 1084 matching lines @@
     if (rowLayoutObject) {
       rowLayoutObject->setLocation(LayoutPoint(0, m_rowPos[r]));
       rowLayoutObject->setLogicalWidth(logicalWidth());
       rowLayoutObject->setLogicalHeight(
           LayoutUnit(m_rowPos[r + 1] - m_rowPos[r] - vspacing));
       rowLayoutObject->updateLayerTransformAfterLayout();
       if (isPaginated) {
         paginationStrutOnRow =
             paginationStrutForRow(rowLayoutObject, LayoutUnit(m_rowPos[r]));
         rowLayoutObject->setPaginationStrut(LayoutUnit(paginationStrutOnRow));
-        if (paginationStrutOnRow) {
+        if (paginationStrutOnRow ||
+            needsStrutForTableHeaders(state, LayoutUnit(m_rowPos[r]))) {
           // If there isn't room for at least one content row on a page with a header group, then
           // we won't repeat the header on each page.
           if (!r && table()->header() &&
               table()->sectionAbove(this) == table()->header() &&
               table()->header()->getPaginationBreakability() != AllowAnyBreaks)
             state.setHeightOffsetForTableHeaders(
                 state.heightOffsetForTableHeaders() -
                 table()->header()->logicalHeight());
           // If we have a header group we will paint it at the top of each page, move the rows
           // down to accomodate it.
@@ skipping 144 matching lines @@
   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();
   if (rowLogicalHeight > pageLogicalHeight)
     return 0;
+
   LayoutUnit remainingLogicalHeight = pageRemainingLogicalHeightForOffset(
       logicalOffset, LayoutBlock::AssociateWithLatterPage);
+  LayoutUnit offsetForBorderSpacing =
+      pageLogicalHeight - (remainingLogicalHeight + table()->vBorderSpacing());
+  // Border spacing from the previous row has pushed this row just past the top of the page, so we must reposition it to the top

[mstensho (USE GERRIT), 2016/10/04 21:02:38]

Should wrap this comment at 80 cols.

+  // of the page and avoid any repeating header.
+  if (offsetForBorderSpacing < 0)
+    return offsetForBorderSpacing.toInt();
+
   if (remainingLogicalHeight >= rowLogicalHeight)
     return 0;  // It fits fine where it is. No need to break.
   LayoutUnit paginationStrut = calculatePaginationStrutToFitContent(
       logicalOffset, remainingLogicalHeight, rowLogicalHeight);
   if (paginationStrut == remainingLogicalHeight &&
       remainingLogicalHeight == pageLogicalHeight) {
     // Don't break if we were at the top of a page, and we failed to fit the content
     // completely. No point in leaving a page completely blank.
     return 0;
   }
@@ skipping 650 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 && isRepeatingHeaderGroup())
     rect.setHeight(table()->logicalHeight());
   return LayoutTableBoxComponent::mapToVisualRectInAncestorSpace(ancestor, rect,
                                                                  flags);
 }
 
 }  // namespace blink