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

Source/core/css/CSSCrossfadeValue.cpp

Index: Source/core/css/CSSCrossfadeValue.cpp
diff --git a/Source/core/css/CSSCrossfadeValue.cpp b/Source/core/css/CSSCrossfadeValue.cpp
index 43536472b972fa8c1adccba67c7ba68eaea491a5..41af71c2e596c4daec771cb67e63b6b9bfbf1805 100644
--- a/Source/core/css/CSSCrossfadeValue.cpp
+++ b/Source/core/css/CSSCrossfadeValue.cpp
@@ -117,6 +117,13 @@ String CSSCrossfadeValue::customCSSText() const
     return result.toString();
 }
 
+PassRefPtrWillBeRawPtr<CSSCrossfadeValue> CSSCrossfadeValue::valueWithURLsMadeAbsolute()
+{
+    RefPtrWillBeRawPtr<CSSValue> fromValue = m_fromValue->isImageValue() ? toCSSImageValue(*m_fromValue).valueWithURLMadeAbsolute() : m_fromValue;
+    RefPtrWillBeRawPtr<CSSValue> toValue = m_toValue->isImageValue() ? toCSSImageValue(*m_toValue).valueWithURLMadeAbsolute() : m_toValue;
+    return CSSCrossfadeValue::create(fromValue.release(), toValue.release(), m_percentageValue);
+}
+
 IntSize CSSCrossfadeValue::fixedSize(const LayoutObject* layoutObject)
 {
     Image* fromImage = renderableImageForCSSValue(m_fromValue.get(), layoutObject);