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

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

Index: third_party/WebKit/Source/core/layout/LayoutTableCell.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableCell.h b/third_party/WebKit/Source/core/layout/LayoutTableCell.h
index 6ce3209bf396e44e4c80f27cb087251db698acdd..f888e6ccfa4b18bb1694e516a4381bf073a06f6c 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCell.h
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCell.h
@@ -317,7 +317,61 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
     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();
   }
@@ -330,6 +384,7 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
   LayoutBox* locationContainer() const override { return section(); }
 
  protected:
+  void ensureIsReadyForPaintInvalidation() override;
   void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
   void computePreferredLogicalWidths() override;
 
@@ -428,6 +483,14 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
   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());