blink: Layers that have a backdrop-filter paints contents

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 a52eabc06ef1b7b06dd4ff4666441073408d3f64..b50a57450f4ee58afe40c3464626c9c6b1d4bc94 100644
--- a/Source/core/style/ComputedStyle.h
+++ b/Source/core/style/ComputedStyle.h
@@ -409,6 +409,7 @@ public:
     bool hasMarginAfterQuirk() const { return marginAfter().quirk(); }
 
     bool hasBackgroundImage() const { return m_background->background().hasImage(); }
+    bool hasBackgroundImageOrBackdropFilter() const { return hasBackgroundImage() || hasBackdropFilter(); }
     bool hasFixedBackgroundImage() const { return m_background->background().hasFixedImage(); }
 
     bool hasEntirelyFixedBackground() const;
@@ -422,7 +423,7 @@ public:
         Color color = visitedDependentColor(CSSPropertyBackgroundColor);
         if (color.alpha())
             return true;
-        return hasBackgroundImage();
+        return hasBackgroundImageOrBackdropFilter();
     }
 
     LayoutRectOutsets imageOutsets(const NinePieceImage&) const;