Stop using SVGElementInstance in SVGElement

Source/core/svg/SVGElement.h

Index: Source/core/svg/SVGElement.h
diff --git a/Source/core/svg/SVGElement.h b/Source/core/svg/SVGElement.h
index 7ccf059d0817ad59cc2a29f26ba2b75a5ef2a5da..c20377b6a6329911214dd86fbe5c94fc69c760f0 100644
--- a/Source/core/svg/SVGElement.h
+++ b/Source/core/svg/SVGElement.h
@@ -40,7 +40,6 @@ class SVGAnimatedPropertyBase;
 class SubtreeLayoutScope;
 class SVGCursorElement;
 class SVGDocumentExtensions;
-class SVGElementInstance;
 class SVGElementRareData;
 class SVGFitToViewBox;
 class SVGSVGElement;
@@ -109,6 +108,8 @@ public:
     void invalidateSVGPresentationAttributeStyle() { ensureUniqueElementData().m_presentationAttributeStyleIsDirty = true; }
 
     const HashSet<SVGElement*>& instancesForElement() const;
+    void mapInstanceToElement(SVGElement*);
+    void removeInstanceMapping(SVGElement*);
 
     bool getBoundingBox(FloatRect&);
 
@@ -210,8 +211,6 @@ protected:
     bool hasFocusEventListeners() const;
 
 private:
-    friend class SVGElementInstance;
-
     // FIXME: Author shadows should be allowed
     // https://bugs.webkit.org/show_bug.cgi?id=77938
     virtual bool areAuthorShadowsAllowed() const OVERRIDE FINAL { return false; }
@@ -222,9 +221,6 @@ private:
 
     void buildPendingResourcesIfNeeded();
 
-    void mapInstanceToElement(SVGElementInstance*);
-    void removeInstanceMapping(SVGElementInstance*);
-
     bool supportsSpatialNavigationFocus() const;
 
     HashSet<SVGElement*> m_elementsWithRelativeLengths;