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 f3b067dadd0e090a5ec86ff8ed07e9f97801a152..3145a831c081da7bc5ae9182235986102d60b6d4 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCell.h
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCell.h
@@ -288,12 +288,12 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
   bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const override;
   void invalidateDisplayItemClients(PaintInvalidationReason) const override;
 
+  // TODO(wkorman): Consider making this a struct again as it once was.
   // TODO(wkorman): Consider renaming to more clearly differentiate from
   // CollapsedBorderValue.
-  class CollapsedBorderValues : public DisplayItemClient {
+  class CollapsedBorderValues {
    public:
-    CollapsedBorderValues(const LayoutTable&,
-                          const CollapsedBorderValue& startBorder,
+    CollapsedBorderValues(const CollapsedBorderValue& startBorder,
                           const CollapsedBorderValue& endBorder,
                           const CollapsedBorderValue& beforeBorder,
                           const CollapsedBorderValue& afterBorder);
@@ -305,19 +305,31 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
 
     void setCollapsedBorderValues(const CollapsedBorderValues& other);
 
+   private:
+    CollapsedBorderValue m_startBorder;
+    CollapsedBorderValue m_endBorder;
+    CollapsedBorderValue m_beforeBorder;
+    CollapsedBorderValue m_afterBorder;
+  };
+
+  // Composited table cells may paint content such as borders and backgrounds
+  // into their table's graphics layer. In such cases we must use the table's
+  // visual rect for that painting. Thus, we use this class to act as a separate
+  // display item client for unique id purposes on a per-cell basis.
+  class CompositedTableCell : public DisplayItemClient {
+   public:
+    CompositedTableCell(const LayoutTable&);
+
     // DisplayItemClient methods.
     String debugName() const;
     LayoutRect visualRect() const;
 
    private:
     const LayoutTable& m_layoutTable;
-    CollapsedBorderValue m_startBorder;
-    CollapsedBorderValue m_endBorder;
-    CollapsedBorderValue m_beforeBorder;
-    CollapsedBorderValue m_afterBorder;
   };
 
   bool usesTableAsAdditionalDisplayItemClient() const;
+  const CompositedTableCell* compositedTableCell() const;
   const CollapsedBorderValues* collapsedBorderValues() const {
     return m_collapsedBorderValues.get();
   }
@@ -330,6 +342,7 @@ 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;
 
@@ -432,6 +445,7 @@ class CORE_EXPORT LayoutTableCell final : public LayoutBlockFlow {
   int m_intrinsicPaddingAfter;
 
   std::unique_ptr<CollapsedBorderValues> m_collapsedBorderValues;
+  std::unique_ptr<CompositedTableCell> m_compositedTableCell;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableCell, isTableCell());