Fix table cell background painting

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

Index: third_party/WebKit/Source/core/paint/TableCellPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/TableCellPainter.cpp b/third_party/WebKit/Source/core/paint/TableCellPainter.cpp
index d30a77340c74afe4822b12116fa57d3f56be879b..6ec9a7322643feead5c8c5378a03ab5277481676 100644
--- a/third_party/WebKit/Source/core/paint/TableCellPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/TableCellPainter.cpp
@@ -5,6 +5,7 @@
 #include "core/paint/TableCellPainter.h"
 
 #include "core/layout/LayoutTableCell.h"
+#include "core/layout/LayoutTableCol.h"
 #include "core/paint/BlockPainter.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ -140,10 +141,12 @@ void TableCellPainter::paintCollapsedBorders(const PaintInfo& paintInfo, const L
     }
 }
 
-void TableCellPainter::paintBackgroundsBehindCell(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutObject* backgroundObject, DisplayItem::Type type)
+void TableCellPainter::paintBackgroundsBehindCell(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutBox& backgroundObject, DisplayItem::Type type)
 {
-    if (!backgroundObject)
+    if (RuntimeEnabledFeatures::newTableCellBackgroundPaintingEnabled() && &backgroundObject != &m_layoutTableCell) {
+        paintParentBackgroundsBehindCell(paintInfo, paintOffset, backgroundObject, type);
         return;
+    }
 
     if (m_layoutTableCell.style()->visibility() != VISIBLE)
         return;
@@ -152,11 +155,11 @@ void TableCellPainter::paintBackgroundsBehindCell(const PaintInfo& paintInfo, co
     if (!tableElt->collapseBorders() && m_layoutTableCell.style()->emptyCells() == EmptyCellsHide && !m_layoutTableCell.firstChild())
         return;
 
-    LayoutRect paintRect = paintBounds(paintOffset, backgroundObject != &m_layoutTableCell ? AddOffsetFromParent : DoNotAddOffsetFromParent);
+    LayoutRect paintRect = paintBounds(paintOffset, &backgroundObject != &m_layoutTableCell ? AddOffsetFromParent : DoNotAddOffsetFromParent);
 
     // Record drawing only if the cell is painting background from containers.
     Optional<LayoutObjectDrawingRecorder> recorder;
-    if (backgroundObject != &m_layoutTableCell) {
+    if (&backgroundObject != &m_layoutTableCell) {
         if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_layoutTableCell, type))
             return;
         recorder.emplace(paintInfo.context, m_layoutTableCell, type, paintRect);
@@ -164,19 +167,62 @@ void TableCellPainter::paintBackgroundsBehindCell(const PaintInfo& paintInfo, co
         ASSERT(paintRect.location() == paintOffset);
     }
 
-    Color c = backgroundObject->resolveColor(CSSPropertyBackgroundColor);
-    const FillLayer& bgLayer = backgroundObject->style()->backgroundLayers();
+    Color c = backgroundObject.resolveColor(CSSPropertyBackgroundColor);
+    const FillLayer& bgLayer = backgroundObject.style()->backgroundLayers();
     if (bgLayer.hasImage() || c.alpha()) {
         // We have to clip here because the background would paint
         // on top of the borders otherwise.  This only matters for cells and rows.
-        bool shouldClip = backgroundObject->hasLayer() && (backgroundObject == &m_layoutTableCell || backgroundObject == m_layoutTableCell.parent()) && tableElt->collapseBorders();
+        bool shouldClip = backgroundObject.hasLayer() && (&backgroundObject == &m_layoutTableCell || &backgroundObject == m_layoutTableCell.parent()) && tableElt->collapseBorders();
         GraphicsContextStateSaver stateSaver(paintInfo.context, shouldClip);
         if (shouldClip) {
             LayoutRect clipRect(paintRect.location(), m_layoutTableCell.size());
             clipRect.expand(m_layoutTableCell.borderInsets());
             paintInfo.context.clip(pixelSnappedIntRect(clipRect));
         }
-        BoxPainter(m_layoutTableCell).paintFillLayers(paintInfo, c, bgLayer, paintRect, BackgroundBleedNone, SkXfermode::kSrcOver_Mode, backgroundObject);
+        BoxPainter(m_layoutTableCell).paintFillLayers(paintInfo, c, bgLayer, paintRect, BackgroundBleedNone, SkXfermode::kSrcOver_Mode, &backgroundObject);
+    }
+}
+
+void TableCellPainter::paintParentBackgroundsBehindCell(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutBox& backgroundObject, DisplayItem::Type type)
+{
+
+    if (m_layoutTableCell.style()->visibility() != VISIBLE)
+        return;
+
+    LayoutTable* table = m_layoutTableCell.table();
+    if (!table->collapseBorders() && m_layoutTableCell.style()->emptyCells() == EmptyCellsHide && !m_layoutTableCell.firstChild())
+        return;
+
+    LayoutRect backgroundRect = paintBoundsParent(paintOffset, backgroundObject, type);
+
+    LayoutRect cellRect = m_layoutTableCell.frameRect();
+    cellRect.moveBy(paintOffset);
+
+    cellRect.setLocation(LayoutPoint(cellRect.pixelSnappedLocation()));
+    cellRect.setSize(LayoutSize(cellRect.pixelSnappedSize()));
+
+    LayoutRect paintRect = backgroundRect;
+    paintRect.unite(cellRect);
+
+    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_layoutTableCell, type)) {
+        return;
+    }
+    LayoutObjectDrawingRecorder recorder(paintInfo.context, m_layoutTableCell, type, paintRect);
+
+    Color color = backgroundObject.resolveColor(CSSPropertyBackgroundColor);
+    const FillLayer& backgroundLayer = backgroundObject.style()->backgroundLayers();
+
+    // TODO(crbug.com/598489) background image paints incorrectly when rowspan/colspan > 1,
+    // and background-image-size is in '%'
+
+    if (backgroundLayer.hasImage() || color.alpha()) {
+
+        GraphicsContextStateSaver stateSaver(paintInfo.context, true);
+        LayoutRect clipRect(m_layoutTableCell.location(), m_layoutTableCell.size());
+        clipRect.moveBy(paintOffset);
+        paintInfo.context.clip(pixelSnappedIntRect(clipRect));
+
+        BoxPainter(backgroundObject).paintFillLayers(paintInfo, color, backgroundLayer, paintRect, BackgroundBleedNone, SkXfermode::kSrcOver_Mode, &backgroundObject);
     }
 }
 
@@ -203,7 +249,7 @@ void TableCellPainter::paintBoxDecorationBackground(const PaintInfo& paintInfo,
     BoxPainter::paintBoxShadow(paintInfo, paintRect, m_layoutTableCell.styleRef(), Normal);
 
     // Paint our cell background.
-    paintBackgroundsBehindCell(paintInfo, paintOffset, &m_layoutTableCell, DisplayItem::BoxDecorationBackground);
+    paintBackgroundsBehindCell(paintInfo, paintOffset, m_layoutTableCell, DisplayItem::BoxDecorationBackground);
 
     BoxPainter::paintBoxShadow(paintInfo, paintRect, m_layoutTableCell.styleRef(), Inset);
 
@@ -238,5 +284,42 @@ LayoutRect TableCellPainter::paintBounds(const LayoutPoint& paintOffset, PaintBo
     return LayoutRect(adjustedPaintOffset, LayoutSize(m_layoutTableCell.pixelSnappedSize()));
 }
 
+LayoutRect TableCellPainter::paintBoundsParent(const LayoutPoint& paintOffset, const LayoutBox& backgroundObject, DisplayItem::Type type)
+{
+    LayoutRect position;
+    switch (type) {
+    case DisplayItem::TableCellBackgroundFromColumnGroup:
+    case DisplayItem::TableCellBackgroundFromColumn: {
+        position = static_cast<const LayoutTableCol&>(backgroundObject).positionForBackgroundDrawing(
+            m_layoutTableCell.absoluteColumnIndex());
+        // position is relative to table, must correct for section location
+        LayoutPoint sectionLocation = m_layoutTableCell.section()->location();
+        position.moveBy(-sectionLocation);
+        position.moveBy(paintOffset);
+        break;
+    }
+    case DisplayItem::TableCellBackgroundFromSection: {
+        position = static_cast<const LayoutTableSection&>(backgroundObject).positionForBackgroundDrawing();
+        position.moveBy(paintOffset);
+        break;
+    }
+    case DisplayItem::TableCellBackgroundFromRow: {
+        position = static_cast<const LayoutTableRow&>(backgroundObject).positionForBackgroundDrawing();
+        position.moveBy(paintOffset);
+        break;
+    }
+    case DisplayItem::BoxDecorationBackground: {
+        LayoutPoint adjustedPaintOffset = paintOffset;
+        adjustedPaintOffset.moveBy(m_layoutTableCell.location());
+        position =  LayoutRect(adjustedPaintOffset, LayoutSize(m_layoutTableCell.size()));
+        break;
+    }
+    default:
+        ASSERT_NOT_REACHED();
+        break;
+    }
+    return LayoutRect(position.pixelSnappedLocation(), position.pixelSnappedSize());
+}
+
 } // namespace blink