Repeating header groups should align properly when captions are present

third_party/WebKit/Source/core/paint/TableSectionPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/TableSectionPainter.h"
 
 #include "core/layout/LayoutTableCell.h"
 #include "core/layout/LayoutTableCol.h"
 #include "core/layout/LayoutTableRow.h"
 #include "core/paint/BoxClipper.h"
@@ skipping 53 matching lines @@
   // Now move paginationOffset to the top of the page the cull rect starts on.
   if (paintInfo.cullRect().m_rect.y() > paginationOffset.y())
     paginationOffset.move(
         0, pageHeight.toInt() *
                ((paintInfo.cullRect().m_rect.y() - paginationOffset.y()) /
                 pageHeight)
                    .toInt());
   LayoutUnit bottomBound =
       std::min(LayoutUnit(paintInfo.cullRect().m_rect.maxY()),
                paintOffset.y() + table->logicalHeight());
+  paginationOffset.move(0, -m_layoutTableSection.logicalTop().toInt());

[mstensho (USE GERRIT), 2016/10/18 17:08:49]

LayoutUnit() is cheaper than 0.

   while (paginationOffset.y() < bottomBound) {
     LayoutPoint nestedOffset =
         paginationOffset +
         LayoutPoint(0, m_layoutTableSection.offsetForRepeatingHeader().toInt());
     if (itemToPaint == PaintCollapsedBorders)
       paintCollapsedSectionBorders(paintInfo, nestedOffset, currentBorderValue);
     else
       paintSection(paintInfo, nestedOffset);
     paginationOffset.move(0, pageHeight.toInt());
   }
@@ skipping 306 matching lines @@
   LayoutRect bounds = BoxPainter(m_layoutTableSection)
                           .boundsForDrawingRecorder(paintInfo, paintOffset);
   LayoutObjectDrawingRecorder recorder(paintInfo.context, m_layoutTableSection,
                                        type, bounds);
   BoxPainter::paintBoxShadow(
       paintInfo, LayoutRect(paintOffset, m_layoutTableSection.size()),
       m_layoutTableSection.styleRef(), shadowStyle);
 }
 
 }  // namespace blink