Paint collapsed borders of a table as one display item

third_party/WebKit/Source/core/paint/PaintLayer.h

Index: third_party/WebKit/Source/core/paint/PaintLayer.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.h b/third_party/WebKit/Source/core/paint/PaintLayer.h
index 21f32a0bed73a086d96b347bfeae2a616dfc2bf3..70d8e5786d6addd5d393c1fd02ebc4c801b433b1 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.h
@@ -55,6 +55,7 @@
 #include "core/paint/PaintLayerScrollableArea.h"
 #include "core/paint/PaintLayerStackingNode.h"
 #include "core/paint/PaintLayerStackingNodeIterator.h"
+#include "core/paint/PaintResult.h"
 #include "platform/graphics/CompositingReasons.h"
 #include "platform/graphics/SquashingDisallowedReasons.h"
 #include "wtf/Allocator.h"
@@ -924,10 +925,10 @@ class CORE_EXPORT PaintLayer : public DisplayItemClient {
     m_previousPaintDirtyRect = rect;
   }
 
-  PaintLayerPainter::PaintResult previousPaintResult() const {
-    return static_cast<PaintLayerPainter::PaintResult>(m_previousPaintResult);
+  PaintResult previousPaintResult() const {
+    return static_cast<PaintResult>(m_previousPaintResult);
   }
-  void setPreviousPaintResult(PaintLayerPainter::PaintResult result) {
+  void setPreviousPaintResult(PaintResult result) {
     m_previousPaintResult = static_cast<unsigned>(result);
     DCHECK(m_previousPaintResult == static_cast<unsigned>(result));
   }
@@ -1182,7 +1183,9 @@ class CORE_EXPORT PaintLayer : public DisplayItemClient {
   unsigned m_lostGroupedMapping : 1;
 
   unsigned m_needsRepaint : 1;
-  unsigned m_previousPaintResult : 1;  // PaintLayerPainter::PaintResult
+  unsigned m_previousPaintResult : 1;  // PaintResult
+  static_assert(MaxPaintResult <= 2,
+                "Should update number of bits of m_previousPaintResult");
 
   unsigned m_needsPaintPhaseDescendantOutlines : 1;
   unsigned m_previousPaintPhaseDescendantOutlinesWasEmpty : 1;