BackgroundImage incorrectly returns empty url() when created on-the-fly

Source/core/css/CSSImageGeneratorValue.cpp

Index: Source/core/css/CSSImageGeneratorValue.cpp
diff --git a/Source/core/css/CSSImageGeneratorValue.cpp b/Source/core/css/CSSImageGeneratorValue.cpp
index 77806a70b619836c83515c9294cc15b92b16c656..83b837ace7ec69dd56b3f337e08cfb47c9e23bf8 100644
--- a/Source/core/css/CSSImageGeneratorValue.cpp
+++ b/Source/core/css/CSSImageGeneratorValue.cpp
@@ -66,6 +66,13 @@ void CSSImageGeneratorValue::addClient(LayoutObject* layoutObject, const IntSize
     }
 }
 
+PassRefPtrWillBeRawPtr<CSSImageGeneratorValue> CSSImageGeneratorValue::valueWithAbsoluteURL()
+{
+    if (isCrossfadeValue())
+        return toCSSCrossfadeValue(this)->valueWithAbsoluteURL();
+    return this;
+}
+
 void CSSImageGeneratorValue::removeClient(LayoutObject* layoutObject)
 {
     ASSERT(layoutObject);