NOT FOR LANDING Experiment with allocating SVGImageForContainer on demand

Source/core/fetch/ImageResource.h

Index: Source/core/fetch/ImageResource.h
diff --git a/Source/core/fetch/ImageResource.h b/Source/core/fetch/ImageResource.h
index ebf080284b313d1564ac74dfef116abbb1ca920c..cd821ff8a90985e9e9b9792800f8c47d20c53057 100644
--- a/Source/core/fetch/ImageResource.h
+++ b/Source/core/fetch/ImageResource.h
@@ -41,7 +41,6 @@ class Length;
 class MemoryCache;
 class LayoutObject;
 class SecurityOrigin;
-class SVGImageForContainer;
 
 class CORE_EXPORT ImageResource final : public Resource, public ImageObserver {
     friend class MemoryCache;
@@ -71,7 +70,6 @@ public:
 
     bool canRender(const LayoutObject& layoutObject, float multiplier) { return !errorOccurred() && !imageSizeForLayoutObject(&layoutObject, multiplier).isEmpty(); }
 
-    void setContainerSizeForLayoutObject(const ImageResourceClient*, const IntSize&, float);
     bool usesImageContainerSize() const;
     bool imageHasRelativeWidth() const;
     bool imageHasRelativeHeight() const;
@@ -141,15 +139,10 @@ private:
     void clearImage();
     // If not null, changeRect is the changed part of the image.
     void notifyObservers(const IntRect* changeRect = nullptr);
-    IntSize svgImageSizeForLayoutObject(const LayoutObject*) const;
-    blink::Image* svgImageForLayoutObject(const LayoutObject*);
     bool loadingMultipartContent() const;
 
     float m_devicePixelRatioHeaderValue;
 
-    typedef HashMap<const ImageResourceClient*, RefPtr<SVGImageForContainer>> ImageForContainerMap;
-    OwnPtr<ImageForContainerMap> m_imageForContainerMap;
-
     RefPtr<blink::Image> m_image;
     bool m_hasDevicePixelRatioHeaderValue;
 };