Use appropriate background object visual rect for composited table cell backgrounds.

third_party/WebKit/Source/core/layout/LayoutTableCell.h

 /*
  * 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, 2009, 2013 Apple Inc.
  *               All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 299 matching lines @@
     LayoutRect visualRect() const;
 
    private:
     const LayoutTable& m_layoutTable;
     CollapsedBorderValue m_startBorder;
     CollapsedBorderValue m_endBorder;
     CollapsedBorderValue m_beforeBorder;
     CollapsedBorderValue m_afterBorder;
   };
 
-  bool usesTableAsAdditionalDisplayItemClient() const;
+  class RowBackgroundDisplayItemClient : public DisplayItemClient {

[wkorman, 2016/11/15 02:30:14]

This class and the two others below are essentially all the same. We could use a
single class def, such as ProxyDisplayItemClient, that takes LayoutObject, and
debugName() could just use that object's debugName with "BackgroundProxy" suffix
or somesuch.

+   public:
+    RowBackgroundDisplayItemClient(const LayoutTableRow&);
+
+    // DisplayItemClient methods.
+    String debugName() const;
+    LayoutRect visualRect() const;
+
+   private:
+    const LayoutTableRow& m_layoutTableRow;
+  };
+
+  class ColBackgroundDisplayItemClient : public DisplayItemClient {
+   public:
+    ColBackgroundDisplayItemClient(const LayoutTableCol&);
+
+    // DisplayItemClient methods.
+    String debugName() const;
+    LayoutRect visualRect() const;
+
+   private:
+    const LayoutTableCol& m_layoutTableCol;
+  };
+
+  class SectionBackgroundDisplayItemClient : public DisplayItemClient {
+   public:
+    SectionBackgroundDisplayItemClient(const LayoutTableSection&);
+
+    // DisplayItemClient methods.
+    String debugName() const;
+    LayoutRect visualRect() const;
+
+   private:
+    const LayoutTableSection& m_layoutTableSection;
+  };
+
+  bool usesCompositedCellDisplayItemClients() const;
+  void createCompositedCellDisplayItemClients();
+  // The special background display item client instances below are only created
+  // for composited table cells when their associated styling warrants per
+  // createCompositedCellDisplayItemClients().
+  const RowBackgroundDisplayItemClient* rowBackgroundDisplayItemClient() const {
+    return m_rowBackgroundDisplayItemClient.get();
+  }
+  const ColBackgroundDisplayItemClient* colBackgroundDisplayItemClient() const {
+    return m_colBackgroundDisplayItemClient.get();
+  }
+  const ColBackgroundDisplayItemClient* colGroupBackgroundDisplayItemClient()
+      const {
+    return m_colGroupBackgroundDisplayItemClient.get();
+  }
+  const SectionBackgroundDisplayItemClient* sectionBackgroundDisplayItemClient()
+      const {
+    return m_sectionBackgroundDisplayItemClient.get();
+  }
   const CollapsedBorderValues* collapsedBorderValues() const {
     return m_collapsedBorderValues.get();
   }
 
   LayoutRect debugRect() const override;
 
   void adjustChildDebugRect(LayoutRect&) const override;
 
   // A table cell's location is relative to its containing section.
   LayoutBox* locationContainer() const override { return section(); }
 
  protected:
+  void ensureIsReadyForPaintInvalidation() override;
   void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
   void computePreferredLogicalWidths() override;
 
   void addLayerHitTestRects(LayerHitTestRects&,
                             const PaintLayer* currentCompositedLayer,
                             const LayoutPoint& layerOffset,
                             const LayoutRect& containerRect) const override;
 
  private:
   bool isOfType(LayoutObjectType type) const override {
@@ skipping 78 matching lines @@
 
   // The intrinsic padding.
   // See class comment for what they are.
   //
   // Note: Those fields are using non-subpixel units (int)
   // because we don't do fractional arithmetic on tables.
   int m_intrinsicPaddingBefore;
   int m_intrinsicPaddingAfter;
 
   std::unique_ptr<CollapsedBorderValues> m_collapsedBorderValues;
+  std::unique_ptr<RowBackgroundDisplayItemClient>

[wkorman, 2016/11/15 01:05:33]

We could use RareData to turn this batch of pointers into one, but probably
better to do later if memory/perf shows warranted.

+      m_rowBackgroundDisplayItemClient;
+  std::unique_ptr<ColBackgroundDisplayItemClient>
+      m_colBackgroundDisplayItemClient;
+  std::unique_ptr<ColBackgroundDisplayItemClient>
+      m_colGroupBackgroundDisplayItemClient;
+  std::unique_ptr<SectionBackgroundDisplayItemClient>
+      m_sectionBackgroundDisplayItemClient;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableCell, isTableCell());
 
 inline LayoutTableCell* LayoutTableCell::previousCell() const {
   return toLayoutTableCell(LayoutObject::previousSibling());
 }
 
 inline LayoutTableCell* LayoutTableCell::nextCell() const {
   return toLayoutTableCell(LayoutObject::nextSibling());
 }
 
 inline LayoutTableCell* LayoutTableRow::firstCell() const {
   return toLayoutTableCell(firstChild());
 }
 
 inline LayoutTableCell* LayoutTableRow::lastCell() const {
   return toLayoutTableCell(lastChild());
 }
 
 }  // namespace blink
 
 #endif  // LayoutTableCell_h