Disallow cast/implicit conversion from LayoutUnit to int/unsigned

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 32 matching lines @@
     LayoutTable* table = m_layoutTableSection.table();
     LayoutPoint paginationOffset = paintOffset;
     LayoutUnit pageHeight = table->pageLogicalHeightForOffset(LayoutUnit());
 
     // Move paginationOffset to the top of the next page.
     // The header may have a pagination strut before it so we need to account for that when establishing its position.
     LayoutUnit headerGroupOffset = table->pageLogicalOffset();
     if (LayoutTableRow* row = m_layoutTableSection.firstRow())
         headerGroupOffset += m_layoutTableSection.paginationStrutForRow(row, table->pageLogicalOffset());
     LayoutUnit offsetToNextPage = pageHeight - intMod(headerGroupOffset, pageHeight);
-    paginationOffset.move(0, offsetToNextPage);
+    paginationOffset.move(0, offsetToNextPage.toInt());
     // 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 * static_cast<int>((paintInfo.cullRect().m_rect.y() - paginationOffset.y()) / pageHeight));
+    if (paintInfo.cullRect().m_rect.y() > paginationOffset.y()) {
+        // TODO(crbug.com/638981): Is the first conversion to int intentional?

[Stephen Chennney, 2016/08/22 17:46:10]

I suspect so. Tables are still laid out at int resolution, which leaves us with
all sorts of annoying bugs. Next gen layout will fix it, but for now I suspect
this is right.

[Xianzhu, 2016/08/22 18:14:38]

Done.

+        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());
     while (paginationOffset.y() < bottomBound) {
-        LayoutPoint nestedOffset = paginationOffset + LayoutPoint(0, m_layoutTableSection.offsetForRepeatingHeader());
+        // TODO(crbug.com/638981): Is the conversion to int (in LayoutPoint(0, ...)) intentional?

[Xianzhu, 2016/08/22 18:14:38]

Removed.

+        LayoutPoint nestedOffset = paginationOffset + LayoutPoint(0, m_layoutTableSection.offsetForRepeatingHeader().toInt());
         if (itemToPaint == PaintCollapsedBorders)
             paintCollapsedSectionBorders(paintInfo, nestedOffset, currentBorderValue);
         else
             paintSection(paintInfo, nestedOffset);
-        paginationOffset.move(0, pageHeight);
+        // TODO(crbug.com/638981): Is the conversion to int (in move(0, ...)) intentional?

[Xianzhu, 2016/08/22 18:14:38]

Removed.

+        paginationOffset.move(0, pageHeight.toInt());
     }
 }
 
 void TableSectionPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     paintSection(paintInfo, paintOffset);
     LayoutTable* table = m_layoutTableSection.table();
     if (table->header() == m_layoutTableSection)
         paintRepeatingHeaderGroup(paintInfo, paintOffset, CollapsedBorderValue(), PaintSection);
 }
@@ skipping 225 matching lines @@
     DisplayItem::Type type = shadowStyle == Normal ? DisplayItem::TableSectionBoxShadowNormal : DisplayItem::TableSectionBoxShadowInset;
     if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_layoutTableSection, type))
         return;
 
     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