Check renderability of images in a (-webkit-)cross-fade before using

Source/core/css/CSSCrossfadeValue.cpp

 /*
  * Copyright (C) 2011 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 66 matching lines @@
         toCSSImageGeneratorValue(value)->loadSubimages(document);
         // FIXME: Handle CSSImageGeneratorValue (and thus cross-fades with gradients and canvas).
         return 0;
     }
 
     ASSERT_NOT_REACHED();
 
     return 0;
 }
 
+static Image* renderableImageForCSSValue(CSSValue* value, const LayoutObject* layoutObject)
+{
+    ImageResource* cachedImage = cachedImageForCSSValue(value, &layoutObject->document());
+
+    // If the image can be rendered at 1 zoom it will have non-empty dimension
+    // and should be able to render at other scales as well.
+    if (!cachedImage || !cachedImage->canRender(*layoutObject, 1))
+        return nullptr;
+
+    return cachedImage->imageForLayoutObject(layoutObject);
+}
+
 CSSCrossfadeValue::~CSSCrossfadeValue()
 {
     if (m_cachedFromImage)
         m_cachedFromImage->removeClient(&m_crossfadeSubimageObserver);
     if (m_cachedToImage)
         m_cachedToImage->removeClient(&m_crossfadeSubimageObserver);
 }
 
 String CSSCrossfadeValue::customCSSText() const
 {
     StringBuilder result;
     result.appendLiteral("-webkit-cross-fade(");
     result.append(m_fromValue->cssText());
     result.appendLiteral(", ");
     result.append(m_toValue->cssText());
     result.appendLiteral(", ");
     result.append(m_percentageValue->cssText());
     result.append(')');
     return result.toString();
 }
 
 IntSize CSSCrossfadeValue::fixedSize(const LayoutObject* layoutObject)
 {
-    float percentage = m_percentageValue->getFloatValue();
-    float inversePercentage = 1 - percentage;
+    Image* fromImage = renderableImageForCSSValue(m_fromValue.get(), layoutObject);
+    Image* toImage = renderableImageForCSSValue(m_toValue.get(), layoutObject);
 
-    Document* document = &layoutObject->document();
-    ImageResource* cachedFromImage = cachedImageForCSSValue(m_fromValue.get(), document);
-    ImageResource* cachedToImage = cachedImageForCSSValue(m_toValue.get(), document);
-
-    if (!cachedFromImage || !cachedToImage)
+    if (!fromImage || !toImage)
         return IntSize();
 
-    IntSize fromImageSize = cachedFromImage->imageForLayoutObject(layoutObject)->size();
-    IntSize toImageSize = cachedToImage->imageForLayoutObject(layoutObject)->size();
+    IntSize fromImageSize = fromImage->size();
+    IntSize toImageSize = toImage->size();
 
     // Rounding issues can cause transitions between images of equal size to return
     // a different fixed size; avoid performing the interpolation if the images are the same size.
     if (fromImageSize == toImageSize)
         return fromImageSize;
 
+    float percentage = m_percentageValue->getFloatValue();
+    float inversePercentage = 1 - percentage;
+
     return IntSize(fromImageSize.width() * inversePercentage + toImageSize.width() * percentage,
         fromImageSize.height() * inversePercentage + toImageSize.height() * percentage);
 }
 
 bool CSSCrossfadeValue::isPending() const
 {
     return subimageIsPending(m_fromValue.get()) || subimageIsPending(m_toValue.get());
 }
 
 bool CSSCrossfadeValue::knownToBeOpaque(const LayoutObject* layoutObject) const
@@ skipping 24 matching lines @@
     }
 
     m_crossfadeSubimageObserver.setReady(true);
 }
 
 PassRefPtr<Image> CSSCrossfadeValue::image(LayoutObject* layoutObject, const IntSize& size)
 {
     if (size.isEmpty())
         return nullptr;
 
-    Document* document = &layoutObject->document();
-    ImageResource* cachedFromImage = cachedImageForCSSValue(m_fromValue.get(), document);
-    ImageResource* cachedToImage = cachedImageForCSSValue(m_toValue.get(), document);
-
-    if (!cachedFromImage || !cachedToImage)
-        return Image::nullImage();
-
-    Image* fromImage = cachedFromImage->imageForLayoutObject(layoutObject);
-    Image* toImage = cachedToImage->imageForLayoutObject(layoutObject);
+    Image* fromImage = renderableImageForCSSValue(m_fromValue.get(), layoutObject);
+    Image* toImage = renderableImageForCSSValue(m_toValue.get(), layoutObject);
 
     if (!fromImage || !toImage)
         return Image::nullImage();
 
     m_generatedImage = CrossfadeGeneratedImage::create(fromImage, toImage, m_percentageValue->getFloatValue(), fixedSize(layoutObject), size);
 
     return m_generatedImage.release();
 }
 
 void CSSCrossfadeValue::crossfadeChanged(const IntRect&)
@@ skipping 29 matching lines @@
 DEFINE_TRACE_AFTER_DISPATCH(CSSCrossfadeValue)
 {
     visitor->trace(m_fromValue);
     visitor->trace(m_toValue);
     visitor->trace(m_percentageValue);
     visitor->trace(m_crossfadeSubimageObserver);
     CSSImageGeneratorValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink