NOT FOR LANDING Experiment with allocating SVGImageForContainer on demand

Source/core/style/StyleGeneratedImage.h

Index: Source/core/style/StyleGeneratedImage.h
diff --git a/Source/core/style/StyleGeneratedImage.h b/Source/core/style/StyleGeneratedImage.h
index 8112e2d3ccdd271a2f2aaa680adc96033ca419f9..78dee10d28a265ef05b76b24dbd6150d353de865 100644
--- a/Source/core/style/StyleGeneratedImage.h
+++ b/Source/core/style/StyleGeneratedImage.h
@@ -48,11 +48,11 @@ public:
     bool imageHasRelativeHeight() const override { return !m_fixedSize; }
     void computeIntrinsicDimensions(const LayoutObject*, Length& intrinsicWidth, Length& intrinsicHeight, FloatSize& intrinsicRatio) override;
     bool usesImageContainerSize() const override { return !m_fixedSize; }
-    void setContainerSizeForLayoutObject(const LayoutObject*, const IntSize& containerSize, float) override { m_containerSize = containerSize; }
     void addClient(LayoutObject*) override;
     void removeClient(LayoutObject*) override;
     PassRefPtr<Image> image(LayoutObject*, const IntSize&) const override;
     bool knownToBeOpaque(const LayoutObject*) const override;
+    KURL url() const override { return KURL(); }
 
     DECLARE_VIRTUAL_TRACE();