LayoutObject::adjustStyleDifference doesn't check backgroundColor when repainting

Source/core/style/ComputedStyle.h

Index: Source/core/style/ComputedStyle.h
diff --git a/Source/core/style/ComputedStyle.h b/Source/core/style/ComputedStyle.h
index e8f1dd447b7c3da63b8cea7aa1f136bd3b89779c..d04e35e75b77e583c5d133110a67cc44c71b8ff3 100644
--- a/Source/core/style/ComputedStyle.h
+++ b/Source/core/style/ComputedStyle.h
@@ -415,11 +415,17 @@ public:
 
     bool hasAppearance() const { return appearance() != NoControlPart; }
 
+    bool isBackgroundColorCurrentColor() const
+    {
+        return backgroundColor().isCurrentColor() || visitedLinkBackgroundColor().isCurrentColor();
+    }
+
     bool hasBackground() const
     {
         Color color = visitedDependentColor(CSSPropertyBackgroundColor);
-        if (color.alpha())
+        if (color.alpha()) {
             return true;
+        }
         return hasBackgroundImage();
     }