Images from content:url() aren't loading if the alt attribute is present

Source/core/layout/LayoutImage.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011-2012. All rights reserved.
  *
@@ skipping 92 matching lines @@
 
     if (hasBoxDecorationBackground() || hasMask() || hasShapeOutside())
         LayoutReplaced::imageChanged(newImage, rect);
 
     if (!m_imageResource)
         return;
 
     if (newImage != m_imageResource->imagePtr())
         return;
 
+    if (isGeneratedContent() && isHTMLImageElement(node()) && m_imageResource->errorOccurred())  {
+        toHTMLImageElement(node())->ensureFallbackForGeneratedContent();
+        return;
+    }
+
     // Per the spec, we let the server-sent header override srcset/other sources of dpr.
     // https://github.com/igrigorik/http-client-hints/blob/master/draft-grigorik-http-client-hints-01.txt#L255
     if (m_imageResource->cachedImage() && m_imageResource->cachedImage()->hasDevicePixelRatioHeaderValue()) {
         UseCounter::count(&(view()->frameView()->frame()), UseCounter::ClientHintsContentDPR);
         m_imageDevicePixelRatio = 1 / m_imageResource->cachedImage()->devicePixelRatioHeaderValue();
     }
 
     if (!m_didIncrementVisuallyNonEmptyPixelCount) {
         // At a zoom level of 1 the image is guaranteed to have an integer size.
         view()->frameView()->incrementVisuallyNonEmptyPixelCount(flooredIntSize(m_imageResource->imageSize(1.0f)));
@@ skipping 243 matching lines @@
         return nullptr;
 
     ImageResource* cachedImage = m_imageResource->cachedImage();
     if (cachedImage && cachedImage->image() && cachedImage->image()->isSVGImage())
         return toSVGImage(cachedImage->image())->embeddedContentBox();
 
     return nullptr;
 }
 
 } // namespace blink