NOT FOR LANDING Experiment with allocating SVGImageForContainer on demand

Source/core/style/StylePendingImage.h

Index: Source/core/style/StylePendingImage.h
diff --git a/Source/core/style/StylePendingImage.h b/Source/core/style/StylePendingImage.h
index 8a00d6d36f786d8fdd979851fe9d1ced7cf48a69..76477e5def7119bc99b6c893b6e170f9a1052ce8 100644
--- a/Source/core/style/StylePendingImage.h
+++ b/Source/core/style/StylePendingImage.h
@@ -59,7 +59,6 @@ public:
     bool imageHasRelativeHeight() const override { return false; }
     void computeIntrinsicDimensions(const LayoutObject*, Length& /* intrinsicWidth */ , Length& /* intrinsicHeight */, FloatSize& /* intrinsicRatio */) override { }
     bool usesImageContainerSize() const override { return false; }
-    void setContainerSizeForLayoutObject(const LayoutObject*, const IntSize&, float) override { }
     void addClient(LayoutObject*) override { }
     void removeClient(LayoutObject*) override { }
     PassRefPtr<Image> image(LayoutObject*, const IntSize&) const override
@@ -68,6 +67,7 @@ public:
         return nullptr;
     }
     bool knownToBeOpaque(const LayoutObject*) const override { return false; }
+    KURL url() const override { return KURL(); }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {