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

Source/core/style/StyleFetchedImage.cpp

Index: Source/core/style/StyleFetchedImage.cpp
diff --git a/Source/core/style/StyleFetchedImage.cpp b/Source/core/style/StyleFetchedImage.cpp
index 5f3d9d007bae15292386c4ff5aa78bf896b5b7ec..29ec9b55b1715d03292f45b49dbeeedd083614f8 100644
--- a/Source/core/style/StyleFetchedImage.cpp
+++ b/Source/core/style/StyleFetchedImage.cpp
@@ -49,6 +49,11 @@ PassRefPtrWillBeRawPtr<CSSValue> StyleFetchedImage::cssValue() const
     return CSSImageValue::create(m_image->url(), const_cast<StyleFetchedImage*>(this));
 }
 
+PassRefPtrWillBeRawPtr<CSSValue> StyleFetchedImage::computedCSSValue() const
+{
+    return cssValue();
+}
+
 bool StyleFetchedImage::canRender(const LayoutObject& layoutObject, float multiplier) const
 {
     return m_image->canRender(layoutObject, multiplier);